better algorithm to load bytes

This commit is contained in:
2026-03-27 18:59:36 -06:00
parent c6c63d6391
commit 3d80b690c4
9 changed files with 135 additions and 89 deletions

View File

@@ -111,21 +111,7 @@ namespace spider {
* Immediate Addressing Mode
*/
void CPU::imm() {
switch(_size) {
case 0b00:
_alu->_u8 = _reel->readU8(RI);
break;
case 0b01:
_alu->_u16 = _reel->readU16(RI);
break;
case 0b10:
_alu->_u32 = _reel->readU32(RI);
break;
case 0b11:
_alu->_u64 = _reel->readU64(RI);
break;
}
_reel->loadRegister(RI, _size, _alu);
_opers[0] = _alu;
_post = &CPU::imp;
RI += 1 << _size;
@@ -134,51 +120,28 @@ namespace spider {
/**
* Absolute Addressing Mode
*/
void CPU::abs() { // TODO cache ptr size
u8 dat_size = 1 << _size;
u8 ptr_size = 1 << getFlag(CPU::FLAG_MEMORY_MODE);
u64 ptr = 0;
void CPU::abs() {
// Load the actual ptr into the ALU
u8 mm = u8(getFlag(CPU::FLAG_MEMORY_MODE));
_reel->loadRegister(RI, mm, _alu);
RI += 1 << mm;
if(ptr_size + dat_size > _ram->size()) return; // TODO: avoid overflow
switch(ptr_size) {
case 1:
ptr = _reel->readU8(RI);
break;
case 2:
ptr = _reel->readU16(RI);
break;
case 4:
ptr = _reel->readU32(RI);
break;
case 8:
ptr = _reel->readU64(RI);
break;
}
switch(_size) {
case 0b00:
spider::loadLE(&_alu->_u8, &(*_ram)[ptr]);
break;
case 0b01:
spider::loadLE(&_alu->_u16, &(*_ram)[ptr]);
break;
case 0b10:
spider::loadLE(&_alu->_u32, &(*_ram)[ptr]);
break;
case 0b11:
spider::loadLE(&_alu->_u64, &(*_ram)[ptr]);
break;
}
RI += dat_size;
// read the memory from RAM
_store = _alu->_u64;
_ram->loadRegister(_store, _size, _alu);
_post = &CPU::psw;
}
/**
* Register Addressing Mode
*/
void CPU::reg() {
void CPU::reg() { // NOT FINISHED
// Two consecutive registers can be declared
// Shift if the top part will become .reg too
u8 sh = (_addrm & 0b11000 == 0b11000) * 4;
// store no-op
_post = &CPU::imp;
}
/**