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paoda:april-fools
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compare: paoda:10255004077e61ef55732827fa8c9d6e35cd5abc
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paoda:april-fools
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paoda:apu-things

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85ffdf44f5 ... 1025500407

2 changed files with 3 additions and 35 deletions
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27
src/cpu/arm/data_processing.zig
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@ -29,18 +29,6 @@ pub fn dataProcessing(comptime I: bool, comptime S: bool, comptime instrKind: u4
}
switch (instrKind) {
0x2 => {
// SUB
const result = op1 -% op2;
cpu.r[rd] = result;
if (S and rd != 0xF) {
cpu.cpsr.n.write(result >> 31 & 1 == 1);
cpu.cpsr.z.write(result == 0);
cpu.cpsr.c.write(op2 <= op1);
cpu.cpsr.v.write(((op1 ^ result) & (~op2 ^ result)) >> 31 & 1 == 1);
}
},
0x4 => {
// ADD
var result: u32 = undefined;
@ -79,7 +67,7 @@ pub fn dataProcessing(comptime I: bool, comptime S: bool, comptime instrKind: u4
if (S and rd != 0xF) {
cpu.cpsr.n.write(op2 >> 31 & 1 == 1);
cpu.cpsr.z.write(op2 == 0);
// C set by Barrel Shifter, V is unaffected
// C set by Barr0x15el Shifter, V is unnafected
}
},
0xA => {
@ -99,18 +87,7 @@ pub fn dataProcessing(comptime I: bool, comptime S: bool, comptime instrKind: u4
if (S and rd != 0xF) {
cpu.cpsr.n.write(result >> 31 & 1 == 1);
cpu.cpsr.z.write(result == 0);
// C set by Barrel Shifter, V is unaffected
}
},
0xF => {
// MVN
const result = ~op2;
cpu.r[rd] = result;
if (S and rd != 0xF) {
cpu.cpsr.n.write(result >> 31 & 1 == 1);
cpu.cpsr.z.write(result == 0);
// C set by Barrel Shifter, V is unaffected
// C set by Barr0x15el Shifter, V is unnafected
}
},
else => std.debug.panic("[CPU] TODO: implement data processing type {}", .{instrKind}),

11
src/cpu/thumb/format3.zig
View File

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