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chore: don't write to CPSR + swap with SPSR at the same time

This commit is contained in:
Rekai Nyangadzayi Musuka 2022-09-28 10:01:52 -03:00
parent 750fdb65ae
commit f13b08b527
1 changed files with 39 additions and 52 deletions
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33
src/core/cpu/arm/data_processing.zig
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@ -75,27 +75,25 @@ pub fn dataProcessing(comptime I: bool, comptime S: bool, comptime kind: u4) Ins
0x8, 0x9, 0xA, 0xB => {}, // Test Operations
else => {
cpu.r[rd] = result;
if (rd == 0xF) cpu.pipe.reload(u32, cpu);
if (rd == 0xF) {
if (S) cpu.setCpsr(cpu.spsr.raw);
cpu.pipe.reload(u32, cpu);
}
},
}
// Write Flags
switch (kind) {
0x0, 0x1, 0xC, 0xD, 0xE, 0xF => {
0x0, 0x1, 0xC, 0xD, 0xE, 0xF => if (S and rd != 0xF) {
// Logic Operation Flags
if (S) {
if (rd == 0xF) {
cpu.setCpsr(cpu.spsr.raw);
} else {
cpu.cpsr.n.write(result >> 31 & 1 == 1);
cpu.cpsr.z.write(result == 0);
// C set by Barrel Shifter, V is unaffected
}
}
},
0x2, 0x3 => {
0x2, 0x3 => if (S and rd != 0xF) {
// SUB, RSB Flags
if (S) {
cpu.cpsr.n.write(result >> 31 & 1 == 1);
cpu.cpsr.z.write(result == 0);
@ -108,24 +106,16 @@ pub fn dataProcessing(comptime I: bool, comptime S: bool, comptime kind: u4) Ins
cpu.cpsr.c.write(op1 <= op2);
cpu.cpsr.v.write(((op2 ^ result) & (~op1 ^ result)) >> 31 & 1 == 1);
}
if (rd == 0xF) cpu.setCpsr(cpu.spsr.raw);
}
},
0x4, 0x5 => {
0x4, 0x5 => if (S and rd != 0xF) {
// ADD, ADC Flags
if (S) {
cpu.cpsr.n.write(result >> 31 & 1 == 1);
cpu.cpsr.z.write(result == 0);
cpu.cpsr.c.write(didOverflow);
cpu.cpsr.v.write(((op1 ^ result) & (op2 ^ result)) >> 31 & 1 == 1);
if (rd == 0xF) cpu.setCpsr(cpu.spsr.raw);
}
},
0x6, 0x7 => {
0x6, 0x7 => if (S and rd != 0xF) {
// SBC, RSC Flags
if (S) {
cpu.cpsr.n.write(result >> 31 & 1 == 1);
cpu.cpsr.z.write(result == 0);
@ -140,9 +130,6 @@ pub fn dataProcessing(comptime I: bool, comptime S: bool, comptime kind: u4) Ins
cpu.cpsr.c.write(subtrahend <= op2);
cpu.cpsr.v.write(((op2 ^ result) & (~op1 ^ result)) >> 31 & 1 == 1);
}
if (rd == 0xF) cpu.setCpsr(cpu.spsr.raw);
}
},
0x8, 0x9, 0xA, 0xB => {
// Test Operation Flags