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fix(cpu): resolve reversed if statement + write back on W = 0

This commit is contained in:
Rekai Nyangadzayi Musuka 2022-01-04 01:57:37 -06:00
parent 8d8cedea59
commit 8cabcd8901
1 changed files with 2 additions and 2 deletions
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4
src/cpu/single_data_transfer.zig
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@ -13,7 +13,7 @@ pub fn comptimeSingleDataTransfer(comptime I: bool, comptime P: bool, comptime U
const rd = opcode >> 12 & 0xF; const rd = opcode >> 12 & 0xF;
const base = cpu.r[rn]; const base = cpu.r[rn];
const offset = if (I) opcode & 0xFFF else registerOffset(cpu, opcode); const offset = if (I) registerOffset(cpu, opcode) else opcode & 0xFFF;
const modified_base = if (U) base + offset else base - offset; const modified_base = if (U) base + offset else base - offset;
var address = if (P) modified_base else base; var address = if (P) modified_base else base;
@ -40,7 +40,7 @@ pub fn comptimeSingleDataTransfer(comptime I: bool, comptime P: bool, comptime U
} }
address = modified_base; address = modified_base;
if (W and P) cpu.r[rn] = address; if (W and P or !W) cpu.r[rn] = address;
// TODO: W-bit forces non-privledged mode for the transfer // TODO: W-bit forces non-privledged mode for the transfer
} }