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fix(cpu): make LDRH and STRH aware of r15

This commit is contained in:
Rekai Nyangadzayi Musuka 2022-01-12 06:26:10 -04:00
parent 5812b9713c
commit 229f7c3388
1 changed files with 9 additions and 2 deletions
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11
src/cpu/half_signed_data_transfer.zig
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@ -13,7 +13,13 @@ pub fn halfAndSignedDataTransfer(comptime P: bool, comptime U: bool, comptime I:
const rm = opcode & 0xF;
const imm_offset_high = opcode >> 8 & 0xF;
const base = cpu.r[rn];
var base: u32 = undefined;
if (rn == 0xF) {
base = cpu.fakePC();
if (!L) base += 4;
} else {
base = cpu.r[rn];
}
var offset: u32 = undefined;
if (I) {
@ -33,7 +39,8 @@ pub fn halfAndSignedDataTransfer(comptime P: bool, comptime U: bool, comptime I:
},
0b01 => {
// LDRH
cpu.r[rd] = bus.read16(address);
const value = bus.read16(address & 0xFFFF_FFFE);
cpu.r[rd] = std.math.rotr(u32, @as(u32, value), 8 * (address & 1));
},
0b10 => {
// LDRSB