Files
ircolib/core/broadway/instructions.cpp
T
2026-05-12 17:55:05 +02:00

98 lines
2.5 KiB
C++

#include <broadway/utils.hpp>
#include "ircolib/log.hpp"
#include <mem.hpp>
namespace weee::core {
void broadway::addi(ircolib::u32 instr) {
if (utils::RA(instr) == 0) { // lis
gpr[utils::RD(instr)] = ircolib::s32(utils::SIMM(instr));
return;
}
gpr[utils::RD(instr)] = gpr[utils::RA(instr)] + (ircolib::s32(utils::SIMM(instr)));
}
void broadway::addis(ircolib::u32 instr) {
if (utils::RA(instr) == 0) { // lis
gpr[utils::RD(instr)] = ircolib::s32(utils::SIMM(instr)) << 16;
return;
}
gpr[utils::RD(instr)] = gpr[utils::RA(instr)] + (ircolib::s32(utils::SIMM(instr)) << 16);
}
void broadway::ori(ircolib::u32 instr) { gpr[utils::RA(instr)] = gpr[utils::RS(instr)] | utils::UIMM(instr); }
void broadway::bx(ircolib::u32 instr) {
const bool link = instr & 1;
const bool absolute = instr & 2;
ircolib::s32 LI = (ircolib::s32(instr << 6) >> 6) & 0x03FFFFFC;
if (!absolute)
LI += pc - 4;
if (link)
lr = pc;
pc = LI;
}
void broadway::move_spr(ircolib::u32 instr) {
const size_t spr_field = (instr >> 12) & 0x3FF;
const size_t direction = (instr >> 1) & 0x3FF;
if (direction == 339) {
switch (spr_field) {
case 0x80:
gpr[utils::RD(instr)] = lr;
break;
case 0x90:
gpr[utils::RD(instr)] = ctr;
break;
default:
ircolib::panic("broadway::mfspr with unimplemented spr field of value {}", spr_field);
}
return;
}
if (direction == 467) {
switch (spr_field) {
case 0x80:
lr = gpr[utils::RS(instr)];
break;
case 0x90:
ctr = gpr[utils::RS(instr)];
break;
default:
ircolib::panic("broadway::mtspr with unimplemented spr field of value {}", spr_field);
}
return;
}
ircolib::panic("broadway::move_spr with unknown sub op {}", direction);
}
void broadway::stwu(ircolib::u32 instr, mem &mem) {
if (utils::RA(instr) == 0)
ircolib::panic("broadway::stwu with ra == 0");
const ircolib::s32 d = utils::SIMM(instr);
const ircolib::u32 EA = gpr[utils::RA(instr)] + d;
mem.write(EA, gpr[utils::RS(instr)]);
gpr[utils::RA(instr)] = EA;
}
void broadway::sth(ircolib::u32 instr, mem &mem) {
ircolib::u32 b = gpr[utils::RA(instr)];
if (utils::RA(instr) == 0)
b = 0;
const ircolib::s32 d = utils::SIMM(instr);
const ircolib::u32 EA = b + d;
mem.write(EA, ircolib::u16(gpr[utils::RS(instr)]));
}
} // namespace weee::core