feat(cpu): implement SUB in THUMB format 3
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@ -28,6 +28,7 @@ pub fn format3(comptime op: u2, comptime rd: u3) InstrFn {
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cpu.cpsr.v.write(((left ^ result) & (~offset ^ result)) >> 31 & 1 == 1);
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},
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0b10 => {
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// ADD
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const left = cpu.r[rd];
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var result: u32 = undefined;
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@ -40,7 +41,15 @@ pub fn format3(comptime op: u2, comptime rd: u3) InstrFn {
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cpu.cpsr.v.write(((left ^ result) & (offset ^ result)) >> 31 & 1 == 1);
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},
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0b11 => {
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std.debug.panic("TODO: Implement sub R{}, #0x{X:0>2}", .{ rd, offset });
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// SUB
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const left = cpu.r[rd];
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const result = left -% offset;
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cpu.r[rd] = result;
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cpu.cpsr.n.write(result >> 31 & 1 == 1);
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cpu.cpsr.z.write(result == 0);
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cpu.cpsr.c.write(offset <= left);
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cpu.cpsr.v.write(((left ^ result) & (~offset ^ result)) >> 31 & 1 == 1);
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},
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}
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}
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