moves mmu related code into mmu unit

src/iss/mem/memory_with_htif.h

@@ -0,0 +1,56 @@
+#ifndef _MEMORY_WITH_HTIF_
+#define _MEMORY_WITH_HTIF_
+
+#include "iss/arch/riscv_hart_common.h"
+#include "iss/vm_types.h"
+#include <util/logging.h>
+#include <util/sparse_array.h>
+#include "../mem/memory_if.h"
+
+namespace iss {
+namespace mem {
+template <typename WORD_TYPE> struct memory_with_htif : public memory_elem {
+    using this_class = memory_with_htif<WORD_TYPE>;
+    constexpr static unsigned WORD_LEN = sizeof(WORD_TYPE) * 8;
+
+    memory_with_htif(arch::priv_if<WORD_TYPE> hart_if)
+    : hart_if(hart_if) {}
+
+    ~memory_with_htif() = default;
+
+    memory_if get_mem_if() override {
+        return memory_if{.rd_mem{util::delegate<rd_mem_func_sig>::from<this_class, &this_class::read_mem>(this)},
+                         .wr_mem{util::delegate<wr_mem_func_sig>::from<this_class, &this_class::write_mem>(this)}};
+    }
+
+    void set_next(memory_if) override {
+        // intenrionally left empty, leaf element
+    }
+
+private:
+    iss::status read_mem(iss::access_type access, uint64_t addr, unsigned length, uint8_t* data) {
+        for(auto offs = 0U; offs < length; ++offs) {
+            *(data + offs) = mem[(addr + offs) % mem.size()];
+        }
+        return iss::Ok;
+    }
+
+    iss::status write_mem(iss::access_type access, uint64_t addr, unsigned length, uint8_t const* data) {
+        mem_type::page_type& p = mem(addr / mem.page_size);
+        std::copy(data, data + length, p.data() + (addr & mem.page_addr_mask));
+        // this->tohost handling in case of riscv-test
+        // according to https://github.com/riscv-software-src/riscv-isa-sim/issues/364#issuecomment-607657754:
+        if(access && iss::access_type::FUNC && addr == hart_if.tohost) {
+            return hart_if.exec_htif(data);
+        }
+        return iss::Ok;
+    }
+
+protected:
+    using mem_type = util::sparse_array<uint8_t, 1ULL << 32>;
+    mem_type mem;
+    arch::priv_if<WORD_TYPE> hart_if;
+};
+} // namespace mem
+} // namespace iss
+#endif // _MEMORY_WITH_HTIF_