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fix(cpu): don't ignore 11th bit of THUMB BL offset

This commit is contained in:
Rekai Nyangadzayi Musuka 2022-01-29 23:53:40 -04:00
parent e18f10126e
commit dc6931639f
1 changed files with 2 additions and 2 deletions
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4
src/cpu/thumb/format19.zig
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@ -9,7 +9,7 @@ pub fn format19(comptime is_low: bool) InstrFn {
return struct {
fn inner(cpu: *Arm7tdmi, _: *Bus, opcode: u16) void {
// BL
const offset = opcode & 0x3FF;
const offset = opcode & 0x7FF;
if (is_low) {
// Instruction 2
@ -19,7 +19,7 @@ pub fn format19(comptime is_low: bool) InstrFn {
cpu.r[14] = old_pc | 1;
} else {
// Instruction 1
cpu.r[14] = (cpu.r[15] + 2) + (u32SignExtend(11, @as(u32, offset)) << 12);
cpu.r[14] = (cpu.r[15] + 2) +% (u32SignExtend(11, @as(u32, offset)) << 12);
}
}
}.inner;