CMakeLists.txt

@@ -20,7 +20,6 @@ set(LIB_SOURCES
     src/iss/arch/tgc5c.cpp
     src/vm/interp/vm_tgc5c.cpp
     src/vm/fp_functions.cpp
-    src/vm/instruction_decoder.cpp
     src/iss/semihosting/semihosting.cpp
 )
 

gen_input/templates/asmjit/CORENAME.cpp.gtl

@@ -37,7 +37,6 @@
 #include <iss/asmjit/vm_base.h>
 #include <asmjit/asmjit.h>
 #include <util/logging.h>
-#include <vm/instruction_decoder.h>
 
 #ifndef FMT_HEADER_ONLY
 #define FMT_HEADER_ONLY
@@ -80,16 +79,22 @@ public:
     }
 
 protected:
+    using super::mov;
+    using super::cmp;
     using super::get_ptr_for;
+    using super::get_reg;
+    using super::get_reg_Gp;
     using super::get_reg_for;
     using super::get_reg_for_Gp;
     using super::load_reg_from_mem;
     using super::load_reg_from_mem_Gp;
     using super::write_reg_to_mem;
+    using super::gen_ext;
     using super::gen_read_mem;
     using super::gen_write_mem;
     using super::gen_wait;
     using super::gen_leave;
+    using super::gen_operation;
     using super::gen_sync;
     using super::gen_set_tval;
    
@@ -116,11 +121,20 @@ private:
      * start opcode definitions
      ****************************************************************************/
     struct instruction_descriptor {
-        uint32_t length;
+        size_t length;
         uint32_t value;
         uint32_t mask;
         compile_func op;
     };
+    struct decoding_tree_node{
+        std::vector<instruction_descriptor> instrs;
+        std::vector<decoding_tree_node*> children;
+        uint32_t submask = std::numeric_limits<uint32_t>::max();
+        uint32_t value;
+        decoding_tree_node(uint32_t value) : value(value){}
+    };
+
+    decoding_tree_node* root {nullptr};
 
     const std::array<instruction_descriptor, ${instructions.size()}> instr_descr = {{
          /* entries are: size, valid value, valid mask, function ptr */<%instructions.each{instr -> %>
@@ -128,9 +142,6 @@ private:
         {${instr.length}, ${instr.encoding}, ${instr.mask}, &this_class::__${generator.functionName(instr.name)}},<%}%>
     }};
  
-    //needs to be declared after instr_descr
-    decoder instr_decoder;
-
     /* instruction definitions */<%instructions.eachWithIndex{instr, idx -> %>
     /* instruction ${idx}: ${instr.name} */
     continuation_e __${generator.functionName(instr.name)}(virt_addr_t& pc, code_word_t instr, jit_holder& jh){
@@ -195,22 +206,72 @@ private:
         gen_instr_epilogue(jh);
         return BRANCH;
     }
+     
+    //decoding functionality
+
+    void populate_decoding_tree(decoding_tree_node* root){
+        //create submask
+        for(auto instr: root->instrs){
+            root->submask &= instr.mask;
+        }
+        //put each instr according to submask&encoding into children
+        for(auto instr: root->instrs){
+            bool foundMatch = false;
+            for(auto child: root->children){
+                //use value as identifying trait
+                if(child->value == (instr.value&root->submask)){
+                    child->instrs.push_back(instr);
+                    foundMatch = true;
+                }
+            }
+            if(!foundMatch){
+                decoding_tree_node* child = new decoding_tree_node(instr.value&root->submask);
+                child->instrs.push_back(instr);
+                root->children.push_back(child);
+            }
+        }
+        root->instrs.clear();
+        //call populate_decoding_tree for all children
+        if(root->children.size() >1)
+            for(auto child: root->children){
+                populate_decoding_tree(child);      
+            }
+        else{
+            //sort instrs by value of the mask, this works bc we want to have the least restrictive one last
+            std::sort(root->children[0]->instrs.begin(), root->children[0]->instrs.end(), [](const instruction_descriptor& instr1, const instruction_descriptor& instr2) {
+            return instr1.mask > instr2.mask;
+            }); 
+        }
+    }
+    compile_func decode_instr(decoding_tree_node* node, code_word_t word){
+        if(!node->children.size()){
+            if(node->instrs.size() == 1) return node->instrs[0].op;
+            for(auto instr : node->instrs){
+                if((instr.mask&word) == instr.value) return instr.op;
+            }
+        }
+        else{
+            for(auto child : node->children){
+                if (child->value == (node->submask&word)){
+                    return decode_instr(child, word);
+                }  
+            }  
+        }
+        return nullptr;
+    }
 };
 
 template <typename ARCH> vm_impl<ARCH>::vm_impl() { this(new ARCH()); }
 
 template <typename ARCH>
 vm_impl<ARCH>::vm_impl(ARCH &core, unsigned core_id, unsigned cluster_id)
-: vm_base<ARCH>(core, core_id, cluster_id)
+: vm_base<ARCH>(core, core_id, cluster_id) {
-, instr_decoder([this]() {
+    root = new decoding_tree_node(std::numeric_limits<uint32_t>::max());
-        std::vector<generic_instruction_descriptor> g_instr_descr;
+    for(auto instr: instr_descr){
-        g_instr_descr.reserve(instr_descr.size());
+        root->instrs.push_back(instr);
-        for (uint32_t i = 0; i < instr_descr.size(); ++i) {
+    }
-            generic_instruction_descriptor new_instr_descr {instr_descr[i].value, instr_descr[i].mask, i};
+    populate_decoding_tree(root);
-            g_instr_descr.push_back(new_instr_descr);
+}
-        }
-        return std::move(g_instr_descr);
-    }()) {}
 
 template <typename ARCH>
 continuation_e vm_impl<ARCH>::gen_single_inst_behavior(virt_addr_t &pc, unsigned int &inst_cnt, jit_holder& jh) {
@@ -226,10 +287,7 @@ continuation_e vm_impl<ARCH>::gen_single_inst_behavior(virt_addr_t &pc, unsigned
     if (instr == 0x0000006f || (instr&0xffff)==0xa001)
         throw simulation_stopped(0); // 'J 0' or 'C.J 0'
     ++inst_cnt;
-    uint32_t inst_index = instr_decoder.decode_instr(instr);
+    auto f = decode_instr(root, instr);
-    compile_func f = nullptr;
-    if(inst_index < instr_descr.size())
-        f = instr_descr[inst_index].op;
     if (f == nullptr) 
         f = &this_class::illegal_instruction;
     return (this->*f)(pc, instr, jh);

gen_input/templates/llvm/CORENAME.cpp.gtl

@@ -36,7 +36,6 @@
 #include <iss/iss.h>
 #include <iss/llvm/vm_base.h>
 #include <util/logging.h>
-#include <vm/instruction_decoder.h>
 
 #ifndef FMT_HEADER_ONLY
 #define FMT_HEADER_ONLY
@@ -137,11 +136,20 @@ private:
      * start opcode definitions
      ****************************************************************************/
     struct instruction_descriptor {
-        uint32_t length;
+        size_t length;
         uint32_t value;
         uint32_t mask;
         compile_func op;
     };
+    struct decoding_tree_node{
+        std::vector<instruction_descriptor> instrs;
+        std::vector<decoding_tree_node*> children;
+        uint32_t submask = std::numeric_limits<uint32_t>::max();
+        uint32_t value;
+        decoding_tree_node(uint32_t value) : value(value){}
+    };
+
+    decoding_tree_node* root {nullptr};
 
     const std::array<instruction_descriptor, ${instructions.size()}> instr_descr = {{
          /* entries are: size, valid value, valid mask, function ptr */<%instructions.each{instr -> %>
@@ -149,9 +157,6 @@ private:
         {${instr.length}, ${instr.encoding}, ${instr.mask}, &this_class::__${generator.functionName(instr.name)}},<%}%>
     }};
  
-    //needs to be declared after instr_descr
-    decoder instr_decoder;
-
     /* instruction definitions */<%instructions.eachWithIndex{instr, idx -> %>
     /* instruction ${idx}: ${instr.name} */
     std::tuple<continuation_e, BasicBlock*> __${generator.functionName(instr.name)}(virt_addr_t& pc, code_word_t instr, BasicBlock* bb){
@@ -214,6 +219,58 @@ private:
         this->builder.CreateBr(bb);
         return std::make_tuple(BRANCH, nullptr);
     }    
+    //decoding functionality
+
+    void populate_decoding_tree(decoding_tree_node* root){
+        //create submask
+        for(auto instr: root->instrs){
+            root->submask &= instr.mask;
+        }
+        //put each instr according to submask&encoding into children
+        for(auto instr: root->instrs){
+            bool foundMatch = false;
+            for(auto child: root->children){
+                //use value as identifying trait
+                if(child->value == (instr.value&root->submask)){
+                    child->instrs.push_back(instr);
+                    foundMatch = true;
+                }
+            }
+            if(!foundMatch){
+                decoding_tree_node* child = new decoding_tree_node(instr.value&root->submask);
+                child->instrs.push_back(instr);
+                root->children.push_back(child);
+            }
+        }
+        root->instrs.clear();
+        //call populate_decoding_tree for all children
+        if(root->children.size() >1)
+            for(auto child: root->children){
+                populate_decoding_tree(child);      
+            }
+        else{
+            //sort instrs by value of the mask, this works bc we want to have the least restrictive one last
+            std::sort(root->children[0]->instrs.begin(), root->children[0]->instrs.end(), [](const instruction_descriptor& instr1, const instruction_descriptor& instr2) {
+            return instr1.mask > instr2.mask;
+            }); 
+        }
+    }
+    compile_func decode_instr(decoding_tree_node* node, code_word_t word){
+        if(!node->children.size()){
+            if(node->instrs.size() == 1) return node->instrs[0].op;
+            for(auto instr : node->instrs){
+                if((instr.mask&word) == instr.value) return instr.op;
+            }
+        }
+        else{
+            for(auto child : node->children){
+                if (child->value == (node->submask&word)){
+                    return decode_instr(child, word);
+                }  
+            }  
+        }
+        return nullptr;
+    }
 };
 
 template <typename CODE_WORD> void debug_fn(CODE_WORD instr) {
@@ -225,16 +282,13 @@ template <typename ARCH> vm_impl<ARCH>::vm_impl() { this(new ARCH()); }
 
 template <typename ARCH>
 vm_impl<ARCH>::vm_impl(ARCH &core, unsigned core_id, unsigned cluster_id)
-: vm_base<ARCH>(core, core_id, cluster_id)
+: vm_base<ARCH>(core, core_id, cluster_id) {
-, instr_decoder([this]() {
+    root = new decoding_tree_node(std::numeric_limits<uint32_t>::max());
-        std::vector<generic_instruction_descriptor> g_instr_descr;
+    for(auto instr:instr_descr){
-        g_instr_descr.reserve(instr_descr.size());
+        root->instrs.push_back(instr);
-        for (uint32_t i = 0; i < instr_descr.size(); ++i) {
+    }
-            generic_instruction_descriptor new_instr_descr {instr_descr[i].value, instr_descr[i].mask, i};
+    populate_decoding_tree(root);
-            g_instr_descr.push_back(new_instr_descr);
+}
-        }
-        return std::move(g_instr_descr);
-    }()) {}
 
 template <typename ARCH>
 std::tuple<continuation_e, BasicBlock *>
@@ -255,16 +309,13 @@ vm_impl<ARCH>::gen_single_inst_behavior(virt_addr_t &pc, unsigned int &inst_cnt,
 //            res = this->core.read(this->core.v2p(pc + 2), 2, data + 2);
 //        }
 //    } else {
-    auto res = this->core.read(paddr, 4, data);
+        auto res = this->core.read(paddr, 4, data);
-    if (res != iss::Ok) throw trap_access(TRAP_ID, pc.val);
+        if (res != iss::Ok) throw trap_access(TRAP_ID, pc.val);
 //    }
     if (instr == 0x0000006f || (instr&0xffff)==0xa001) throw simulation_stopped(0); // 'J 0' or 'C.J 0'
     // curr pc on stack
     ++inst_cnt;
-    uint32_t inst_index = instr_decoder.decode_instr(instr);
+    auto f = decode_instr(root, instr);
-    compile_func f = nullptr;
-    if(inst_index < instr_descr.size())
-        f = instr_descr[inst_index].op;
     if (f == nullptr) {
         f = &this_class::illegal_instruction;
     }

gen_input/templates/tcc/CORENAME.cpp.gtl

@@ -37,7 +37,6 @@
 #include <iss/tcc/vm_base.h>
 #include <util/logging.h>
 #include <sstream>
-#include <vm/instruction_decoder.h>
 
 #ifndef FMT_HEADER_ONLY
 #define FMT_HEADER_ONLY
@@ -138,11 +137,20 @@ private:
      * start opcode definitions
      ****************************************************************************/
     struct instruction_descriptor {
-        uint32_t length;
+        size_t length;
         uint32_t value;
         uint32_t mask;
         compile_func op;
     };
+    struct decoding_tree_node{
+        std::vector<instruction_descriptor> instrs;
+        std::vector<decoding_tree_node*> children;
+        uint32_t submask = std::numeric_limits<uint32_t>::max();
+        uint32_t value;
+        decoding_tree_node(uint32_t value) : value(value){}
+    };
+
+    decoding_tree_node* root {nullptr};
 
     const std::array<instruction_descriptor, ${instructions.size()}> instr_descr = {{
          /* entries are: size, valid value, valid mask, function ptr */<%instructions.each{instr -> %>
@@ -150,9 +158,6 @@ private:
         {${instr.length}, ${instr.encoding}, ${instr.mask}, &this_class::__${generator.functionName(instr.name)}},<%}%>
     }};
  
-    //needs to be declared after instr_descr
-    decoder instr_decoder;
-
     /* instruction definitions */<%instructions.eachWithIndex{instr, idx -> %>
     /* instruction ${idx}: ${instr.name} */
     compile_ret_t __${generator.functionName(instr.name)}(virt_addr_t& pc, code_word_t instr, tu_builder& tu){
@@ -193,6 +198,59 @@ private:
         vm_impl::gen_trap_check(tu);
         return BRANCH;
     }
+    
+    //decoding functionality
+
+    void populate_decoding_tree(decoding_tree_node* root){
+        //create submask
+        for(auto instr: root->instrs){
+            root->submask &= instr.mask;
+        }
+        //put each instr according to submask&encoding into children
+        for(auto instr: root->instrs){
+            bool foundMatch = false;
+            for(auto child: root->children){
+                //use value as identifying trait
+                if(child->value == (instr.value&root->submask)){
+                    child->instrs.push_back(instr);
+                    foundMatch = true;
+                }
+            }
+            if(!foundMatch){
+                decoding_tree_node* child = new decoding_tree_node(instr.value&root->submask);
+                child->instrs.push_back(instr);
+                root->children.push_back(child);
+            }
+        }
+        root->instrs.clear();
+        //call populate_decoding_tree for all children
+        if(root->children.size() >1)
+            for(auto child: root->children){
+                populate_decoding_tree(child);      
+            }
+        else{
+            //sort instrs by value of the mask, this works bc we want to have the least restrictive one last
+            std::sort(root->children[0]->instrs.begin(), root->children[0]->instrs.end(), [](const instruction_descriptor& instr1, const instruction_descriptor& instr2) {
+            return instr1.mask > instr2.mask;
+            }); 
+        }
+    }
+    compile_func decode_instr(decoding_tree_node* node, code_word_t word){
+        if(!node->children.size()){
+            if(node->instrs.size() == 1) return node->instrs[0].op;
+            for(auto instr : node->instrs){
+                if((instr.mask&word) == instr.value) return instr.op;
+            }
+        }
+        else{
+            for(auto child : node->children){
+                if (child->value == (node->submask&word)){
+                    return decode_instr(child, word);
+                }  
+            }  
+        }
+        return nullptr;
+    }
 };
 
 template <typename CODE_WORD> void debug_fn(CODE_WORD instr) {
@@ -204,16 +262,13 @@ template <typename ARCH> vm_impl<ARCH>::vm_impl() { this(new ARCH()); }
 
 template <typename ARCH>
 vm_impl<ARCH>::vm_impl(ARCH &core, unsigned core_id, unsigned cluster_id)
-: vm_base<ARCH>(core, core_id, cluster_id)
+: vm_base<ARCH>(core, core_id, cluster_id) {
-, instr_decoder([this]() {
+    root = new decoding_tree_node(std::numeric_limits<uint32_t>::max());
-        std::vector<generic_instruction_descriptor> g_instr_descr;
+    for(auto instr:instr_descr){
-        g_instr_descr.reserve(instr_descr.size());
+        root->instrs.push_back(instr);
-        for (uint32_t i = 0; i < instr_descr.size(); ++i) {
+    }
-            generic_instruction_descriptor new_instr_descr {instr_descr[i].value, instr_descr[i].mask, i};
+    populate_decoding_tree(root);
-            g_instr_descr.push_back(new_instr_descr);
+}
-        }
-        return std::move(g_instr_descr);
-    }()) {}
 
 template <typename ARCH>
 std::tuple<continuation_e>
@@ -232,16 +287,13 @@ vm_impl<ARCH>::gen_single_inst_behavior(virt_addr_t &pc, unsigned int &inst_cnt,
 //            res = this->core.read(this->core.v2p(pc + 2), 2, data + 2);
 //        }
 //    } else {
-    auto res = this->core.read(paddr, 4, reinterpret_cast<uint8_t*>(&instr));
+        auto res = this->core.read(paddr, 4, reinterpret_cast<uint8_t*>(&instr));
-    if (res != iss::Ok) throw trap_access(TRAP_ID, pc.val);
+        if (res != iss::Ok) throw trap_access(TRAP_ID, pc.val);
 //    }
     if (instr == 0x0000006f || (instr&0xffff)==0xa001) throw simulation_stopped(0); // 'J 0' or 'C.J 0'
     // curr pc on stack
     ++inst_cnt;
-    uint32_t inst_index = instr_decoder.decode_instr(instr);
+    auto f = decode_instr(root, instr);
-    compile_func f = nullptr;
-    if(inst_index < instr_descr.size())
-        f = instr_descr[inst_index].op;
     if (f == nullptr) {
         f = &this_class::illegal_instruction;
     }

src/vm/asmjit/vm_tgc5c.cpp

@@ -37,7 +37,6 @@
 #include <iss/asmjit/vm_base.h>
 #include <asmjit/asmjit.h>
 #include <util/logging.h>
-#include <vm/instruction_decoder.h>
 
 #ifndef FMT_HEADER_ONLY
 #define FMT_HEADER_ONLY
@@ -80,16 +79,22 @@ public:
     }
 
 protected:
+    using super::mov;
+    using super::cmp;
     using super::get_ptr_for;
+    using super::get_reg;
+    using super::get_reg_Gp;
     using super::get_reg_for;
     using super::get_reg_for_Gp;
     using super::load_reg_from_mem;
     using super::load_reg_from_mem_Gp;
     using super::write_reg_to_mem;
+    using super::gen_ext;
     using super::gen_read_mem;
     using super::gen_write_mem;
     using super::gen_wait;
     using super::gen_leave;
+    using super::gen_operation;
     using super::gen_sync;
     using super::gen_set_tval;
    
@@ -116,11 +121,20 @@ private:
      * start opcode definitions
      ****************************************************************************/
     struct instruction_descriptor {
-        uint32_t length;
+        size_t length;
         uint32_t value;
         uint32_t mask;
         compile_func op;
     };
+    struct decoding_tree_node{
+        std::vector<instruction_descriptor> instrs;
+        std::vector<decoding_tree_node*> children;
+        uint32_t submask = std::numeric_limits<uint32_t>::max();
+        uint32_t value;
+        decoding_tree_node(uint32_t value) : value(value){}
+    };
+
+    decoding_tree_node* root {nullptr};
 
     const std::array<instruction_descriptor, 87> instr_descr = {{
          /* entries are: size, valid value, valid mask, function ptr */
@@ -300,9 +314,6 @@ private:
         {16, 0b0000000000000000, 0b1111111111111111, &this_class::__dii},
     }};
  
-    //needs to be declared after instr_descr
-    decoder instr_decoder;
-
     /* instruction definitions */
     /* instruction 0: LUI */
     continuation_e __lui(virt_addr_t& pc, code_word_t instr, jit_holder& jh){
@@ -4735,22 +4746,72 @@ private:
         gen_instr_epilogue(jh);
         return BRANCH;
     }
+     
+    //decoding functionality
+
+    void populate_decoding_tree(decoding_tree_node* root){
+        //create submask
+        for(auto instr: root->instrs){
+            root->submask &= instr.mask;
+        }
+        //put each instr according to submask&encoding into children
+        for(auto instr: root->instrs){
+            bool foundMatch = false;
+            for(auto child: root->children){
+                //use value as identifying trait
+                if(child->value == (instr.value&root->submask)){
+                    child->instrs.push_back(instr);
+                    foundMatch = true;
+                }
+            }
+            if(!foundMatch){
+                decoding_tree_node* child = new decoding_tree_node(instr.value&root->submask);
+                child->instrs.push_back(instr);
+                root->children.push_back(child);
+            }
+        }
+        root->instrs.clear();
+        //call populate_decoding_tree for all children
+        if(root->children.size() >1)
+            for(auto child: root->children){
+                populate_decoding_tree(child);      
+            }
+        else{
+            //sort instrs by value of the mask, this works bc we want to have the least restrictive one last
+            std::sort(root->children[0]->instrs.begin(), root->children[0]->instrs.end(), [](const instruction_descriptor& instr1, const instruction_descriptor& instr2) {
+            return instr1.mask > instr2.mask;
+            }); 
+        }
+    }
+    compile_func decode_instr(decoding_tree_node* node, code_word_t word){
+        if(!node->children.size()){
+            if(node->instrs.size() == 1) return node->instrs[0].op;
+            for(auto instr : node->instrs){
+                if((instr.mask&word) == instr.value) return instr.op;
+            }
+        }
+        else{
+            for(auto child : node->children){
+                if (child->value == (node->submask&word)){
+                    return decode_instr(child, word);
+                }  
+            }  
+        }
+        return nullptr;
+    }
 };
 
 template <typename ARCH> vm_impl<ARCH>::vm_impl() { this(new ARCH()); }
 
 template <typename ARCH>
 vm_impl<ARCH>::vm_impl(ARCH &core, unsigned core_id, unsigned cluster_id)
-: vm_base<ARCH>(core, core_id, cluster_id)
+: vm_base<ARCH>(core, core_id, cluster_id) {
-, instr_decoder([this]() {
+    root = new decoding_tree_node(std::numeric_limits<uint32_t>::max());
-        std::vector<generic_instruction_descriptor> g_instr_descr;
+    for(auto instr: instr_descr){
-        g_instr_descr.reserve(instr_descr.size());
+        root->instrs.push_back(instr);
-        for (uint32_t i = 0; i < instr_descr.size(); ++i) {
+    }
-            generic_instruction_descriptor new_instr_descr {instr_descr[i].value, instr_descr[i].mask, i};
+    populate_decoding_tree(root);
-            g_instr_descr.push_back(new_instr_descr);
+}
-        }
-        return std::move(g_instr_descr);
-    }()) {}
 
 template <typename ARCH>
 continuation_e vm_impl<ARCH>::gen_single_inst_behavior(virt_addr_t &pc, unsigned int &inst_cnt, jit_holder& jh) {
@@ -4766,10 +4827,7 @@ continuation_e vm_impl<ARCH>::gen_single_inst_behavior(virt_addr_t &pc, unsigned
     if (instr == 0x0000006f || (instr&0xffff)==0xa001)
         throw simulation_stopped(0); // 'J 0' or 'C.J 0'
     ++inst_cnt;
-    uint32_t inst_index = instr_decoder.decode_instr(instr);
+    auto f = decode_instr(root, instr);
-    compile_func f = nullptr;
-    if(inst_index < instr_descr.size())
-        f = instr_descr[inst_index].op;
     if (f == nullptr) 
         f = &this_class::illegal_instruction;
     return (this->*f)(pc, instr, jh);

src/vm/instruction_decoder.cpp

@@ -1,103 +0,0 @@
-/*******************************************************************************
- * Copyright (C) 2024 MINRES Technologies GmbH
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are met:
- *
- * 1. Redistributions of source code must retain the above copyright notice,
- *    this list of conditions and the following disclaimer.
- *
- * 2. Redistributions in binary form must reproduce the above copyright notice,
- *    this list of conditions and the following disclaimer in the documentation
- *    and/or other materials provided with the distribution.
- *
- * 3. Neither the name of the copyright holder nor the names of its contributors
- *    may be used to endorse or promote products derived from this software
- *    without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
- * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
- * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
- * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
- * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
- * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
- * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
- * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
- * POSSIBILITY OF SUCH DAMAGE.
- *
- * Contributors:
- *       alex@minres.com - initial implementation
- ******************************************************************************/
-
-#include <algorithm>
-#include <cassert>
-#include <cstddef>
-#include <cstdint>
-#include <limits>
-#include <numeric>
-#include <vector>
-#include <vm/instruction_decoder.h>
-
-decoder::decoder(std::vector<generic_instruction_descriptor> instr_list) {
-    for(auto instr : instr_list) {
-        root.instrs.push_back(instr);
-    }
-    populate_decoding_tree(root);
-}
-
-void decoder::populate_decoding_tree(decoding_tree_node& parent) {
-    // create submask
-    parent.submask =
-        std::accumulate(parent.instrs.begin(), parent.instrs.end(), std::numeric_limits<uint32_t>::max(),
-                        [](int current_submask, const generic_instruction_descriptor& instr) { return current_submask & instr.mask; });
-    //  put each instr according to submask&encoding into children
-    for(auto instr : parent.instrs) {
-        bool foundMatch = false;
-        for(auto& child : parent.children) {
-            // use value as identifying trait
-            if(child.value == (instr.value & parent.submask)) {
-                child.instrs.push_back(instr);
-                foundMatch = true;
-            }
-        }
-        if(!foundMatch) {
-            decoding_tree_node child = decoding_tree_node(instr.value & parent.submask);
-            child.instrs.push_back(instr);
-            parent.children.push_back(child);
-        }
-    }
-    parent.instrs.clear();
-    // call populate_decoding_tree for all children
-    if(parent.children.size() > 1)
-        for(auto& child : parent.children) {
-            populate_decoding_tree(child);
-        }
-    else {
-        // sort instrs by value of the mask, so we have the least restrictive mask last
-        std::sort(parent.children[0].instrs.begin(), parent.children[0].instrs.end(),
-                  [](const generic_instruction_descriptor& instr1, const generic_instruction_descriptor& instr2) {
-                      return instr1.mask > instr2.mask;
-                  });
-    }
-}
-uint32_t decoder::decode_instr(uint32_t word) { return _decode_instr(this->root, word); }
-uint32_t decoder::_decode_instr(decoding_tree_node const& node, uint32_t word) {
-    if(!node.children.size()) {
-        if(node.instrs.size() == 1)
-            return node.instrs[0].index;
-        for(auto instr : node.instrs) {
-            if((instr.mask & word) == instr.value)
-                return instr.index;
-        }
-    } else {
-        for(auto child : node.children) {
-            if(child.value == (node.submask & word)) {
-                return _decode_instr(child, word);
-            }
-        }
-    }
-    return std::numeric_limits<uint32_t>::max();
-}

src/vm/instruction_decoder.h

@@ -1,63 +0,0 @@
-/*******************************************************************************
- * Copyright (C) 2024 MINRES Technologies GmbH
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are met:
- *
- * 1. Redistributions of source code must retain the above copyright notice,
- *    this list of conditions and the following disclaimer.
- *
- * 2. Redistributions in binary form must reproduce the above copyright notice,
- *    this list of conditions and the following disclaimer in the documentation
- *    and/or other materials provided with the distribution.
- *
- * 3. Neither the name of the copyright holder nor the names of its contributors
- *    may be used to endorse or promote products derived from this software
- *    without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
- * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
- * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
- * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
- * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
- * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
- * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
- * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
- * POSSIBILITY OF SUCH DAMAGE.
- *
- * Contributors:
- *       alex@minres.com - initial implementation
- ******************************************************************************/
-
-#include <cstddef>
-#include <cstdint>
-#include <limits>
-#include <vector>
-
-struct generic_instruction_descriptor {
-    uint32_t value;
-    uint32_t mask;
-    uint32_t index;
-};
-
-struct decoding_tree_node {
-    std::vector<generic_instruction_descriptor> instrs;
-    std::vector<decoding_tree_node> children;
-    uint32_t submask = std::numeric_limits<uint32_t>::max();
-    uint32_t value;
-    decoding_tree_node(uint32_t value)
-    : value(value) {}
-};
-class decoder {
-public:
-    decoder(std::vector<generic_instruction_descriptor> instr_list);
-    uint32_t decode_instr(uint32_t word);
-
-private:
-    decoding_tree_node root{decoding_tree_node(std::numeric_limits<uint32_t>::max())};
-    void populate_decoding_tree(decoding_tree_node& root);
-    uint32_t _decode_instr(decoding_tree_node const& node, uint32_t word);
-};

src/vm/interp/vm_tgc5c.cpp

@@ -31,7 +31,6 @@
  *******************************************************************************/
 
 // clang-format off
-#include <cstdint>
 #include <iss/arch/tgc5c.h>
 #include <iss/debugger/gdb_session.h>
 #include <iss/debugger/server.h>
@@ -44,7 +43,6 @@
 #include <exception>
 #include <vector>
 #include <sstream>
-#include <vm/instruction_decoder.h>
 
 #ifndef FMT_HEADER_ONLY
 #define FMT_HEADER_ONLY
@@ -148,11 +146,20 @@ private:
      * start opcode definitions
      ****************************************************************************/
     struct instruction_descriptor {
-        uint32_t length;
+        size_t length;
         uint32_t value;
         uint32_t mask;
         typename arch::traits<ARCH>::opcode_e op;
     };
+    struct decoding_tree_node{
+        std::vector<instruction_descriptor> instrs;
+        std::vector<decoding_tree_node*> children;
+        uint32_t submask = std::numeric_limits<uint32_t>::max();
+        uint32_t value;
+        decoding_tree_node(uint32_t value) : value(value){}
+    };
+
+    decoding_tree_node* root {nullptr};
     const std::array<instruction_descriptor, 87> instr_descr = {{
          /* entries are: size, valid value, valid mask, function ptr */
         {32, 0b00000000000000000000000000110111, 0b00000000000000000000000001111111, arch::traits<ARCH>::opcode_e::LUI},
@@ -243,8 +250,6 @@ private:
         {16, 0b1100000000000010, 0b1110000000000011, arch::traits<ARCH>::opcode_e::C__SWSP},
         {16, 0b0000000000000000, 0b1111111111111111, arch::traits<ARCH>::opcode_e::DII},
     }};
-    //needs to be declared after instr_descr
-    decoder instr_decoder;
 
     iss::status fetch_ins(virt_addr_t pc, uint8_t * data){
         if(this->core.has_mmu()) {
@@ -265,6 +270,58 @@ private:
         }
         return iss::Ok;
     }
+    
+    void populate_decoding_tree(decoding_tree_node* root){
+        //create submask
+        for(auto instr: root->instrs){
+            root->submask &= instr.mask;
+        }
+        //put each instr according to submask&encoding into children
+        for(auto instr: root->instrs){
+            bool foundMatch = false;
+            for(auto child: root->children){
+                //use value as identifying trait
+                if(child->value == (instr.value&root->submask)){
+                    child->instrs.push_back(instr);
+                    foundMatch = true;
+                }
+            }
+            if(!foundMatch){
+                decoding_tree_node* child = new decoding_tree_node(instr.value&root->submask);
+                child->instrs.push_back(instr);
+                root->children.push_back(child);
+            }
+        }
+        root->instrs.clear();
+        //call populate_decoding_tree for all children
+        if(root->children.size() >1)
+            for(auto child: root->children){
+                populate_decoding_tree(child);      
+            }
+        else{
+            //sort instrs by value of the mask, this works bc we want to have the least restrictive one last
+            std::sort(root->children[0]->instrs.begin(), root->children[0]->instrs.end(), [](const instruction_descriptor& instr1, const instruction_descriptor& instr2) {
+            return instr1.mask > instr2.mask;
+            }); 
+        }
+    }
+
+    typename arch::traits<ARCH>::opcode_e  decode_instr(decoding_tree_node* node, code_word_t word){
+        if(!node->children.size()){
+            if(node->instrs.size() == 1) return node->instrs[0].op;
+            for(auto instr : node->instrs){
+                if((instr.mask&word) == instr.value) return instr.op;
+            }
+        }
+        else{
+            for(auto child : node->children){
+                if (child->value == (node->submask&word)){
+                    return decode_instr(child, word);
+                }  
+            }  
+        }
+        return arch::traits<ARCH>::opcode_e::MAX_OPCODE;
+    }
 };
 
 template <typename CODE_WORD> void debug_fn(CODE_WORD insn) {
@@ -290,16 +347,13 @@ constexpr size_t bit_count(uint32_t u) {
 
 template <typename ARCH>
 vm_impl<ARCH>::vm_impl(ARCH &core, unsigned core_id, unsigned cluster_id)
-: vm_base<ARCH>(core, core_id, cluster_id)
+: vm_base<ARCH>(core, core_id, cluster_id) {
-, instr_decoder([this]() {
+    root = new decoding_tree_node(std::numeric_limits<uint32_t>::max());
-        std::vector<generic_instruction_descriptor> g_instr_descr;
+    for(auto instr:instr_descr){
-        g_instr_descr.reserve(instr_descr.size());
+        root->instrs.push_back(instr);
-        for (uint32_t i = 0; i < instr_descr.size(); ++i) {
+    }
-            generic_instruction_descriptor new_instr_descr {instr_descr[i].value, instr_descr[i].mask, i};
+    populate_decoding_tree(root);
-            g_instr_descr.push_back(new_instr_descr);
+}
-        }
-        return std::move(g_instr_descr);
-    }()) {}
 
 inline bool is_icount_limit_enabled(finish_cond_e cond){
     return (cond & finish_cond_e::ICOUNT_LIMIT) == finish_cond_e::ICOUNT_LIMIT;
@@ -336,13 +390,9 @@ typename vm_base<ARCH>::virt_addr_t vm_impl<ARCH>::execute_inst(finish_cond_e co
         } else {
             if (is_jump_to_self_enabled(cond) &&
                     (instr == 0x0000006f || (instr&0xffff)==0xa001)) throw simulation_stopped(0); // 'J 0' or 'C.J 0'
-            uint32_t inst_index = instr_decoder.decode_instr(instr);
+            auto inst_id = decode_instr(root, instr);
-            opcode_e inst_id = arch::traits<ARCH>::opcode_e::MAX_OPCODE;;
-            if(inst_index <instr_descr.size())
-                inst_id = instr_descr.at(instr_decoder.decode_instr(instr)).op;
-
             // pre execution stuff
-            this->core.reg.last_branch = 0;
+             this->core.reg.last_branch = 0;
             if(this->sync_exec && PRE_SYNC) this->do_sync(PRE_SYNC, static_cast<unsigned>(inst_id));
             try{
                 switch(inst_id){

src/vm/llvm/vm_tgc5c.cpp

@@ -36,7 +36,6 @@
 #include <iss/iss.h>
 #include <iss/llvm/vm_base.h>
 #include <util/logging.h>
-#include <vm/instruction_decoder.h>
 
 #ifndef FMT_HEADER_ONLY
 #define FMT_HEADER_ONLY
@@ -137,11 +136,20 @@ private:
      * start opcode definitions
      ****************************************************************************/
     struct instruction_descriptor {
-        uint32_t length;
+        size_t length;
         uint32_t value;
         uint32_t mask;
         compile_func op;
     };
+    struct decoding_tree_node{
+        std::vector<instruction_descriptor> instrs;
+        std::vector<decoding_tree_node*> children;
+        uint32_t submask = std::numeric_limits<uint32_t>::max();
+        uint32_t value;
+        decoding_tree_node(uint32_t value) : value(value){}
+    };
+
+    decoding_tree_node* root {nullptr};
 
     const std::array<instruction_descriptor, 87> instr_descr = {{
          /* entries are: size, valid value, valid mask, function ptr */
@@ -321,9 +329,6 @@ private:
         {16, 0b0000000000000000, 0b1111111111111111, &this_class::__dii},
     }};
  
-    //needs to be declared after instr_descr
-    decoder instr_decoder;
-
     /* instruction definitions */
     /* instruction 0: LUI */
     std::tuple<continuation_e, BasicBlock*> __lui(virt_addr_t& pc, code_word_t instr, BasicBlock* bb){
@@ -4880,6 +4885,58 @@ private:
         this->builder.CreateBr(bb);
         return std::make_tuple(BRANCH, nullptr);
     }    
+    //decoding functionality
+
+    void populate_decoding_tree(decoding_tree_node* root){
+        //create submask
+        for(auto instr: root->instrs){
+            root->submask &= instr.mask;
+        }
+        //put each instr according to submask&encoding into children
+        for(auto instr: root->instrs){
+            bool foundMatch = false;
+            for(auto child: root->children){
+                //use value as identifying trait
+                if(child->value == (instr.value&root->submask)){
+                    child->instrs.push_back(instr);
+                    foundMatch = true;
+                }
+            }
+            if(!foundMatch){
+                decoding_tree_node* child = new decoding_tree_node(instr.value&root->submask);
+                child->instrs.push_back(instr);
+                root->children.push_back(child);
+            }
+        }
+        root->instrs.clear();
+        //call populate_decoding_tree for all children
+        if(root->children.size() >1)
+            for(auto child: root->children){
+                populate_decoding_tree(child);      
+            }
+        else{
+            //sort instrs by value of the mask, this works bc we want to have the least restrictive one last
+            std::sort(root->children[0]->instrs.begin(), root->children[0]->instrs.end(), [](const instruction_descriptor& instr1, const instruction_descriptor& instr2) {
+            return instr1.mask > instr2.mask;
+            }); 
+        }
+    }
+    compile_func decode_instr(decoding_tree_node* node, code_word_t word){
+        if(!node->children.size()){
+            if(node->instrs.size() == 1) return node->instrs[0].op;
+            for(auto instr : node->instrs){
+                if((instr.mask&word) == instr.value) return instr.op;
+            }
+        }
+        else{
+            for(auto child : node->children){
+                if (child->value == (node->submask&word)){
+                    return decode_instr(child, word);
+                }  
+            }  
+        }
+        return nullptr;
+    }
 };
 
 template <typename CODE_WORD> void debug_fn(CODE_WORD instr) {
@@ -4891,16 +4948,13 @@ template <typename ARCH> vm_impl<ARCH>::vm_impl() { this(new ARCH()); }
 
 template <typename ARCH>
 vm_impl<ARCH>::vm_impl(ARCH &core, unsigned core_id, unsigned cluster_id)
-: vm_base<ARCH>(core, core_id, cluster_id)
+: vm_base<ARCH>(core, core_id, cluster_id) {
-, instr_decoder([this]() {
+    root = new decoding_tree_node(std::numeric_limits<uint32_t>::max());
-        std::vector<generic_instruction_descriptor> g_instr_descr;
+    for(auto instr:instr_descr){
-        g_instr_descr.reserve(instr_descr.size());
+        root->instrs.push_back(instr);
-        for (uint32_t i = 0; i < instr_descr.size(); ++i) {
+    }
-            generic_instruction_descriptor new_instr_descr {instr_descr[i].value, instr_descr[i].mask, i};
+    populate_decoding_tree(root);
-            g_instr_descr.push_back(new_instr_descr);
+}
-        }
-        return std::move(g_instr_descr);
-    }()) {}
 
 template <typename ARCH>
 std::tuple<continuation_e, BasicBlock *>
@@ -4921,16 +4975,13 @@ vm_impl<ARCH>::gen_single_inst_behavior(virt_addr_t &pc, unsigned int &inst_cnt,
 //            res = this->core.read(this->core.v2p(pc + 2), 2, data + 2);
 //        }
 //    } else {
-    auto res = this->core.read(paddr, 4, data);
+        auto res = this->core.read(paddr, 4, data);
-    if (res != iss::Ok) throw trap_access(TRAP_ID, pc.val);
+        if (res != iss::Ok) throw trap_access(TRAP_ID, pc.val);
 //    }
     if (instr == 0x0000006f || (instr&0xffff)==0xa001) throw simulation_stopped(0); // 'J 0' or 'C.J 0'
     // curr pc on stack
     ++inst_cnt;
-    uint32_t inst_index = instr_decoder.decode_instr(instr);
+    auto f = decode_instr(root, instr);
-    compile_func f = nullptr;
-    if(inst_index < instr_descr.size())
-        f = instr_descr[inst_index].op;
     if (f == nullptr) {
         f = &this_class::illegal_instruction;
     }

src/vm/tcc/vm_tgc5c.cpp

@@ -37,7 +37,6 @@
 #include <iss/tcc/vm_base.h>
 #include <util/logging.h>
 #include <sstream>
-#include <vm/instruction_decoder.h>
 
 #ifndef FMT_HEADER_ONLY
 #define FMT_HEADER_ONLY
@@ -138,11 +137,20 @@ private:
      * start opcode definitions
      ****************************************************************************/
     struct instruction_descriptor {
-        uint32_t length;
+        size_t length;
         uint32_t value;
         uint32_t mask;
         compile_func op;
     };
+    struct decoding_tree_node{
+        std::vector<instruction_descriptor> instrs;
+        std::vector<decoding_tree_node*> children;
+        uint32_t submask = std::numeric_limits<uint32_t>::max();
+        uint32_t value;
+        decoding_tree_node(uint32_t value) : value(value){}
+    };
+
+    decoding_tree_node* root {nullptr};
 
     const std::array<instruction_descriptor, 87> instr_descr = {{
          /* entries are: size, valid value, valid mask, function ptr */
@@ -322,9 +330,6 @@ private:
         {16, 0b0000000000000000, 0b1111111111111111, &this_class::__dii},
     }};
  
-    //needs to be declared after instr_descr
-    decoder instr_decoder;
-
     /* instruction definitions */
     /* instruction 0: LUI */
     compile_ret_t __lui(virt_addr_t& pc, code_word_t instr, tu_builder& tu){
@@ -3632,6 +3637,59 @@ private:
         vm_impl::gen_trap_check(tu);
         return BRANCH;
     }
+    
+    //decoding functionality
+
+    void populate_decoding_tree(decoding_tree_node* root){
+        //create submask
+        for(auto instr: root->instrs){
+            root->submask &= instr.mask;
+        }
+        //put each instr according to submask&encoding into children
+        for(auto instr: root->instrs){
+            bool foundMatch = false;
+            for(auto child: root->children){
+                //use value as identifying trait
+                if(child->value == (instr.value&root->submask)){
+                    child->instrs.push_back(instr);
+                    foundMatch = true;
+                }
+            }
+            if(!foundMatch){
+                decoding_tree_node* child = new decoding_tree_node(instr.value&root->submask);
+                child->instrs.push_back(instr);
+                root->children.push_back(child);
+            }
+        }
+        root->instrs.clear();
+        //call populate_decoding_tree for all children
+        if(root->children.size() >1)
+            for(auto child: root->children){
+                populate_decoding_tree(child);      
+            }
+        else{
+            //sort instrs by value of the mask, this works bc we want to have the least restrictive one last
+            std::sort(root->children[0]->instrs.begin(), root->children[0]->instrs.end(), [](const instruction_descriptor& instr1, const instruction_descriptor& instr2) {
+            return instr1.mask > instr2.mask;
+            }); 
+        }
+    }
+    compile_func decode_instr(decoding_tree_node* node, code_word_t word){
+        if(!node->children.size()){
+            if(node->instrs.size() == 1) return node->instrs[0].op;
+            for(auto instr : node->instrs){
+                if((instr.mask&word) == instr.value) return instr.op;
+            }
+        }
+        else{
+            for(auto child : node->children){
+                if (child->value == (node->submask&word)){
+                    return decode_instr(child, word);
+                }  
+            }  
+        }
+        return nullptr;
+    }
 };
 
 template <typename CODE_WORD> void debug_fn(CODE_WORD instr) {
@@ -3643,16 +3701,13 @@ template <typename ARCH> vm_impl<ARCH>::vm_impl() { this(new ARCH()); }
 
 template <typename ARCH>
 vm_impl<ARCH>::vm_impl(ARCH &core, unsigned core_id, unsigned cluster_id)
-: vm_base<ARCH>(core, core_id, cluster_id)
+: vm_base<ARCH>(core, core_id, cluster_id) {
-, instr_decoder([this]() {
+    root = new decoding_tree_node(std::numeric_limits<uint32_t>::max());
-        std::vector<generic_instruction_descriptor> g_instr_descr;
+    for(auto instr:instr_descr){
-        g_instr_descr.reserve(instr_descr.size());
+        root->instrs.push_back(instr);
-        for (uint32_t i = 0; i < instr_descr.size(); ++i) {
+    }
-            generic_instruction_descriptor new_instr_descr {instr_descr[i].value, instr_descr[i].mask, i};
+    populate_decoding_tree(root);
-            g_instr_descr.push_back(new_instr_descr);
+}
-        }
-        return std::move(g_instr_descr);
-    }()) {}
 
 template <typename ARCH>
 std::tuple<continuation_e>
@@ -3671,16 +3726,13 @@ vm_impl<ARCH>::gen_single_inst_behavior(virt_addr_t &pc, unsigned int &inst_cnt,
 //            res = this->core.read(this->core.v2p(pc + 2), 2, data + 2);
 //        }
 //    } else {
-    auto res = this->core.read(paddr, 4, reinterpret_cast<uint8_t*>(&instr));
+        auto res = this->core.read(paddr, 4, reinterpret_cast<uint8_t*>(&instr));
-    if (res != iss::Ok) throw trap_access(TRAP_ID, pc.val);
+        if (res != iss::Ok) throw trap_access(TRAP_ID, pc.val);
 //    }
     if (instr == 0x0000006f || (instr&0xffff)==0xa001) throw simulation_stopped(0); // 'J 0' or 'C.J 0'
     // curr pc on stack
     ++inst_cnt;
-    uint32_t inst_index = instr_decoder.decode_instr(instr);
+    auto f = decode_instr(root, instr);
-    compile_func f = nullptr;
-    if(inst_index < instr_descr.size())
-        f = instr_descr[inst_index].op;
     if (f == nullptr) {
         f = &this_class::illegal_instruction;
     }