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chore: misc pipeline fixes

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This commit is contained in:
Rekai Nyangadzayi Musuka
2022-07-13 02:08:31 -03:00
parent 69cf5b12f1
commit 6da9e965bb
4 changed files with 13 additions and 27 deletions
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8
src/cpu.zig
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@@ -329,8 +329,8 @@ pub const Arm7tdmi = struct {
if (!self.bus.io.ime or self.cpsr.i.read()) return;
// log.debug("An interrupt was Handled!", .{});
// retAddr.gba says r15 on it's own is off by -04h in both ARM and THUMB mode
const r15 = self.r[15] + 4;
// FIXME: Is the return address ahead?
const r15 = self.r[15];
const cpsr = self.cpsr.raw;
self.changeMode(.Irq);
@@ -354,10 +354,6 @@ pub const Arm7tdmi = struct {
return self.bus.read(T, self.r[15]);
}
pub fn fakePC(self: *const Self) u32 {
return self.r[15] + 4;
}
fn debug_log(self: *const Self, file: *const File, opcode: u32) void {
if (self.binary_log) {
self.skyLog(file) catch unreachable;

8
src/cpu/arm/block_data_transfer.zig
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@@ -55,8 +55,10 @@ pub fn blockDataTransfer(comptime P: bool, comptime U: bool, comptime S: bool, c
if (L) {
cpu.r[15] = bus.read(u32, und_addr);
cpu.pipe.flush();
} else {
bus.write(u32, und_addr, cpu.r[15] + 8);
// FIXME: Should r15 on write be +12 ahead?
bus.write(u32, und_addr, cpu.r[15] + 4);
}
cpu.r[rn] = if (U) cpu.r[rn] + 0x40 else cpu.r[rn] - 0x40;
@@ -100,9 +102,9 @@ pub fn blockDataTransfer(comptime P: bool, comptime U: bool, comptime S: bool, c
// Always Transfer User mode Registers
// This happens regardless if r15 is in the list
const value = cpu.getUserModeRegister(i);
bus.write(u32, address, value + if (i == 0xF) 8 else @as(u32, 0)); // PC is already 4 ahead to make 12
bus.write(u32, address, value + if (i == 0xF) 4 else @as(u32, 0)); // PC is already 8 ahead to make 12
} else {
bus.write(u32, address, cpu.r[i] + if (i == 0xF) 8 else @as(u32, 0));
bus.write(u32, address, cpu.r[i] + if (i == 0xF) 4 else @as(u32, 0));
}
}
}

16
src/cpu/arm/half_signed_data_transfer.zig
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@@ -15,20 +15,8 @@ pub fn halfAndSignedDataTransfer(comptime P: bool, comptime U: bool, comptime I:
const rm = opcode & 0xF;
const imm_offset_high = opcode >> 8 & 0xF;
var base: u32 = undefined;
if (rn == 0xF) {
base = cpu.fakePC();
if (!L) base += 4;
} else {
base = cpu.r[rn];
}
var offset: u32 = undefined;
if (I) {
offset = imm_offset_high << 4 | rm;
} else {
offset = cpu.r[rm];
}
const base = cpu.r[rn] + if (!L) 4 else @as(u32, 0);
const offset = if (I) imm_offset_high << 4 | rm else cpu.r[rm];
const modified_base = if (U) base +% offset else base -% offset;
var address = if (P) modified_base else base;

8
src/cpu/arm/single_data_transfer.zig
View File

@@ -14,8 +14,8 @@ pub fn singleDataTransfer(comptime I: bool, comptime P: bool, comptime U: bool,
const rn = opcode >> 16 & 0xF;
const rd = opcode >> 12 & 0xF;
// If L is set, there is an offset of 12 from the instruction to the PC
const base = cpu.r[rn] + if (!L) 4 else @as(u32, 0);
// rn is r15 and L is not set, the PC is 12 ahead
const base = cpu.r[rn] + if (!L and rn == 0xF) 4 else @as(u32, 0);
const offset = if (I) shifter.immShift(false, cpu, opcode) else opcode & 0xFFF;
@@ -35,11 +35,11 @@ pub fn singleDataTransfer(comptime I: bool, comptime P: bool, comptime U: bool,
} else {
if (B) {
// STRB
const value = if (rd == 0xF) cpu.r[rd] + 8 else cpu.r[rd];
const value = cpu.r[rd] + if (rd == 0xF) 4 else @as(u32, 0); // PC is 12 ahead
bus.write(u8, address, @truncate(u8, value));
} else {
// STR
const value = if (rd == 0xF) cpu.r[rd] + 8 else cpu.r[rd];
const value = cpu.r[rd] + if (rd == 0xF) 4 else @as(u32, 0);
bus.write(u32, address, value);
}
}