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adds small optimization, clarifies variables in vector_functions

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This commit is contained in:
Eyck-Alexander Jentzsch 2025-02-05 17:04:16 +01:00
parent 3428745a00
commit f7aa51b12e
1 changed files with 24 additions and 19 deletions
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43
src/vm/vector_functions.cpp
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@ -41,6 +41,7 @@
#include <functional>
#include <limits>
#include <math.h>
#include <stdexcept>
namespace softvector {
unsigned RFS = 32;
@ -85,40 +86,44 @@ double vtype_t::lmul() {
return pow(2, signed_vlmul);
}
vreg_view read_vmask(uint8_t* V, uint8_t VLEN, uint16_t elem_count, uint8_t reg_idx) {
vreg_view read_vmask(uint8_t* V, uint16_t VLEN, uint16_t elem_count, uint8_t reg_idx) {
uint8_t* mask_start = V + VLEN / 8 * reg_idx;
return {mask_start, elem_count / 8u}; // this can return size==0 as elem_count can be as low as 1
}
uint64_t vector_load_store(void* core, std::function<bool(void*, uint64_t, uint64_t, uint8_t*)> load_store_fn, uint8_t* V, uint8_t VLEN,
uint8_t vd, uint64_t base_addr, uint64_t vl, uint64_t vstart, vtype_t vtype, bool vm, uint8_t elem_byte_size,
uint64_t elem_count, int8_t EMUL_pow, uint8_t segment_size, int64_t stride) {
uint64_t vector_load_store(void* core, std::function<bool(void*, uint64_t, uint64_t, uint8_t*)> load_store_fn, uint8_t* V, uint16_t VLEN,
uint8_t addressed_register, uint64_t base_addr, uint64_t vl, uint64_t vstart, vtype_t vtype, bool vm,
uint8_t elem_size_byte, uint64_t elem_count, int8_t EMUL_pow, uint8_t segment_size, int64_t stride) {
// eew = elem_size_byte * 8
assert(pow(2, EMUL_pow) * segment_size <= 8);
assert(segment_size > 0);
assert((elem_count & (elem_count - 1)) == 0); // check that elem_count is power of 2
assert(elem_count <= VLEN * RFS / 8);
unsigned eew = elem_byte_size * 8;
unsigned emul_stride = EMUL_pow <= 0 ? 1 : pow(2, EMUL_pow);
assert(emul_stride * segment_size <= 8);
assert(!(vd % emul_stride));
assert(!(addressed_register % emul_stride));
vreg_view mask_view = read_vmask(V, VLEN, elem_count, 0);
// elements w/ index smaller than vstart are in the prestart and get skipped
// body is from vstart to min(elem_count, vl)
for(unsigned idx = vstart; idx < std::min(elem_count, vl); idx++) {
unsigned trap_idx = idx;
// vm decides active body element
uint8_t current_mask_byte = mask_view.get<uint8_t>(idx / 8);
bool mask_active = vm ? 1 : current_mask_byte & (1 << idx % 8);
for(unsigned s_idx = 0; s_idx < segment_size; s_idx++) {
// base + selected vd + current_elem + current_segment
uint8_t* dest_elem = V + (vd * VLEN / 8) + (eew / 8 * idx) + (VLEN / 8 * s_idx * emul_stride);
assert(dest_elem <= V + VLEN * RFS / 8);
if(mask_active) {
uint64_t addr = base_addr + (eew / 8) * (idx * segment_size + s_idx) * stride;
if(!load_store_fn(core, addr, eew / 8, dest_elem))
if(mask_active) {
for(unsigned s_idx = 0; s_idx < segment_size; s_idx++) {
// base + selected register + current_elem + current_segment
uint8_t* addressed_elem = V + (addressed_register * VLEN / 8) + (elem_size_byte * idx) + (VLEN / 8 * s_idx * emul_stride);
assert(addressed_elem <= V + VLEN * RFS / 8);
uint64_t addr = base_addr + (elem_size_byte) * (idx * segment_size + s_idx) * stride;
if(!load_store_fn(core, addr, elem_size_byte, addressed_elem))
return trap_idx;
} else {
}
} else {
for(unsigned s_idx = 0; s_idx < segment_size; s_idx++) {
// base + selected register + current_elem + current_segment
uint8_t* addressed_elem = V + (addressed_register * VLEN / 8) + (elem_size_byte * idx) + (VLEN / 8 * s_idx * emul_stride);
assert(addressed_elem <= V + VLEN * RFS / 8);
// this only updates the first 8 bits, so eew > 8 would not work correctly
*dest_elem = vtype.vma() ? *dest_elem : *dest_elem;
*addressed_elem = vtype.vma() ? *addressed_elem : *addressed_elem;
}
}
}
@ -127,10 +132,10 @@ uint64_t vector_load_store(void* core, std::function<bool(void*, uint64_t, uint6
for(unsigned idx = std::min(elem_count, vl); idx < VLEN / 8; idx++) {
for(unsigned s_idx = 0; s_idx < segment_size; s_idx++) {
// base + selected vd + current_elem + current_segment
uint8_t* dest_elem = V + (vd * VLEN / 8) + (eew / 8 * idx) + (VLEN / 8 * s_idx * emul_stride);
assert(dest_elem <= V + VLEN * RFS / 8);
uint8_t* addressed_elem = V + (addressed_register * VLEN / 8) + (elem_size_byte * idx) + (VLEN / 8 * s_idx * emul_stride);
assert(addressed_elem <= V + VLEN * RFS / 8);
// this only updates the first 8 bits, so eew > 8 would not work correctly
*dest_elem = vtype.vta() ? *dest_elem : *dest_elem;
*addressed_elem = vtype.vta() ? *addressed_elem : *addressed_elem;
}
}
return 0;