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25 changed files with 467 additions and 402 deletions
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51
src/cpu.zig
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@ -16,35 +16,30 @@ const halfAndSignedDataTransfer = @import("cpu/arm/half_signed_data_transfer.zig
const blockDataTransfer = @import("cpu/arm/block_data_transfer.zig").blockDataTransfer; const blockDataTransfer = @import("cpu/arm/block_data_transfer.zig").blockDataTransfer;
const branch = @import("cpu/arm/branch.zig").branch; const branch = @import("cpu/arm/branch.zig").branch;
const branchAndExchange = @import("cpu/arm/branch.zig").branchAndExchange; const branchAndExchange = @import("cpu/arm/branch.zig").branchAndExchange;
const armSoftwareInterrupt = @import("cpu/arm/software_interrupt.zig").armSoftwareInterrupt; const softwareInterrupt = @import("cpu/arm/software_interrupt.zig").softwareInterrupt;
const multiply = @import("cpu/arm/multiply.zig").multiply;
const multiplyLong = @import("cpu/arm/multiply_long.zig").multiplyLong;
const singleDataSwap = @import("cpu/arm/single_data_swap.zig").singleDataSwap; const singleDataSwap = @import("cpu/arm/single_data_swap.zig").singleDataSwap;
const multiply = @import("cpu/arm/multiply.zig").multiply;
const multiplyLong = @import("cpu/arm/multiply.zig").multiplyLong;
// THUMB Instruction Groups // THUMB Instruction Groups
const format1 = @import("cpu/thumb/data_processing.zig").format1; const format1 = @import("cpu/thumb/format1.zig").format1;
const format2 = @import("cpu/thumb/data_processing.zig").format2; const format2 = @import("cpu/thumb/format2.zig").format2;
const format3 = @import("cpu/thumb/data_processing.zig").format3; const format3 = @import("cpu/thumb/format3.zig").format3;
const format12 = @import("cpu/thumb/data_processing.zig").format12; const format4 = @import("cpu/thumb/format4.zig").format4;
const format13 = @import("cpu/thumb/data_processing.zig").format13; const format5 = @import("cpu/thumb/format5.zig").format5;
const format6 = @import("cpu/thumb/format6.zig").format6;
const format4 = @import("cpu/thumb/alu.zig").format4; const format78 = @import("cpu/thumb/format78.zig").format78;
const format5 = @import("cpu/thumb/processing_branch.zig").format5; const format9 = @import("cpu/thumb/format9.zig").format9;
const format10 = @import("cpu/thumb/format10.zig").format10;
const format6 = @import("cpu/thumb/data_transfer.zig").format6; const format11 = @import("cpu/thumb/format11.zig").format11;
const format78 = @import("cpu/thumb/data_transfer.zig").format78; const format12 = @import("cpu/thumb/format12.zig").format12;
const format9 = @import("cpu/thumb/data_transfer.zig").format9; const format13 = @import("cpu/thumb/format13.zig").format13;
const format10 = @import("cpu/thumb/data_transfer.zig").format10; const format14 = @import("cpu/thumb/format14.zig").format14;
const format11 = @import("cpu/thumb/data_transfer.zig").format11; const format15 = @import("cpu/thumb/format15.zig").format15;
const format14 = @import("cpu/thumb/block_data_transfer.zig").format14; const format16 = @import("cpu/thumb/format16.zig").format16;
const format15 = @import("cpu/thumb/block_data_transfer.zig").format15; const format17 = @import("cpu/thumb/format17.zig").format17;
const format18 = @import("cpu/thumb/format18.zig").format18;
const format16 = @import("cpu/thumb/branch.zig").format16; const format19 = @import("cpu/thumb/format19.zig").format19;
const format18 = @import("cpu/thumb/branch.zig").format18;
const format19 = @import("cpu/thumb/branch.zig").format19;
const thumbSoftwareInterrupt = @import("cpu/thumb/software_interrupt.zig").thumbSoftwareInterrupt;
pub const ArmInstrFn = fn (*Arm7tdmi, *Bus, u32) void; pub const ArmInstrFn = fn (*Arm7tdmi, *Bus, u32) void;
pub const ThumbInstrFn = fn (*Arm7tdmi, *Bus, u16) void; pub const ThumbInstrFn = fn (*Arm7tdmi, *Bus, u16) void;
@ -485,7 +480,7 @@ fn thumbPopulate() [0x400]ThumbInstrFn {
lut[i] = format13(S); lut[i] = format13(S);
} else if (i >> 2 & 0xFF == 0xDF) { } else if (i >> 2 & 0xFF == 0xDF) {
lut[i] = thumbSoftwareInterrupt(); lut[i] = format17();
} else if (i >> 6 & 0xF == 0b1000) { } else if (i >> 6 & 0xF == 0b1000) {
const L = i >> 5 & 1 == 1; const L = i >> 5 & 1 == 1;
const offset = i & 0x1F; const offset = i & 0x1F;
@ -619,7 +614,7 @@ fn armPopulate() [0x1000]ArmInstrFn {
lut[i] = armUndefined; lut[i] = armUndefined;
} else if (i >> 8 & 0xF == 0b1111) { } else if (i >> 8 & 0xF == 0b1111) {
// Bits 27:24 // Bits 27:24
lut[i] = armSoftwareInterrupt(); lut[i] = softwareInterrupt();
} }
} }

33
src/cpu/arm/multiply.zig
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@ -24,36 +24,3 @@ pub fn multiply(comptime A: bool, comptime S: bool) InstrFn {
} }
}.inner; }.inner;
} }
pub fn multiplyLong(comptime U: bool, comptime A: bool, comptime S: bool) InstrFn {
return struct {
fn inner(cpu: *Arm7tdmi, _: *Bus, opcode: u32) void {
const rd_hi = opcode >> 16 & 0xF;
const rd_lo = opcode >> 12 & 0xF;
const rs = opcode >> 8 & 0xF;
const rm = opcode & 0xF;
if (U) {
// Signed (WHY IS IT U THEN?)
var result: i64 = @as(i64, @bitCast(i32, cpu.r[rm])) * @as(i64, @bitCast(i32, cpu.r[rs]));
if (A) result +%= @bitCast(i64, @as(u64, cpu.r[rd_hi]) << 32 | @as(u64, cpu.r[rd_lo]));
cpu.r[rd_hi] = @bitCast(u32, @truncate(i32, result >> 32));
cpu.r[rd_lo] = @bitCast(u32, @truncate(i32, result));
} else {
// Unsigned
var result: u64 = @as(u64, cpu.r[rm]) * @as(u64, cpu.r[rs]);
if (A) result +%= @as(u64, cpu.r[rd_hi]) << 32 | @as(u64, cpu.r[rd_lo]);
cpu.r[rd_hi] = @truncate(u32, result >> 32);
cpu.r[rd_lo] = @truncate(u32, result);
}
if (S) {
cpu.cpsr.z.write(cpu.r[rd_hi] == 0 and cpu.r[rd_lo] == 0);
cpu.cpsr.n.write(cpu.r[rd_hi] >> 31 & 1 == 1);
// C and V are set to meaningless values
}
}
}.inner;
}

38
src/cpu/arm/multiply_long.zig Normal file
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@ -0,0 +1,38 @@
const std = @import("std");
const Bus = @import("../../Bus.zig");
const Arm7tdmi = @import("../../cpu.zig").Arm7tdmi;
const InstrFn = @import("../../cpu.zig").ArmInstrFn;
pub fn multiplyLong(comptime U: bool, comptime A: bool, comptime S: bool) InstrFn {
return struct {
fn inner(cpu: *Arm7tdmi, _: *Bus, opcode: u32) void {
const rd_hi = opcode >> 16 & 0xF;
const rd_lo = opcode >> 12 & 0xF;
const rs = opcode >> 8 & 0xF;
const rm = opcode & 0xF;
if (U) {
// Signed (WHY IS IT U THEN?)
var result: i64 = @as(i64, @bitCast(i32, cpu.r[rm])) * @as(i64, @bitCast(i32, cpu.r[rs]));
if (A) result +%= @bitCast(i64, @as(u64, cpu.r[rd_hi]) << 32 | @as(u64, cpu.r[rd_lo]));
cpu.r[rd_hi] = @bitCast(u32, @truncate(i32, result >> 32));
cpu.r[rd_lo] = @bitCast(u32, @truncate(i32, result));
} else {
// Unsigned
var result: u64 = @as(u64, cpu.r[rm]) * @as(u64, cpu.r[rs]);
if (A) result +%= @as(u64, cpu.r[rd_hi]) << 32 | @as(u64, cpu.r[rd_lo]);
cpu.r[rd_hi] = @truncate(u32, result >> 32);
cpu.r[rd_lo] = @truncate(u32, result);
}
if (S) {
cpu.cpsr.z.write(cpu.r[rd_hi] == 0 and cpu.r[rd_lo] == 0);
cpu.cpsr.n.write(cpu.r[rd_hi] >> 31 & 1 == 1);
// C and V are set to meaningless values
}
}
}.inner;
}

2
src/cpu/arm/software_interrupt.zig
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@ -4,7 +4,7 @@ const Bus = @import("../../Bus.zig");
const Arm7tdmi = @import("../../cpu.zig").Arm7tdmi; const Arm7tdmi = @import("../../cpu.zig").Arm7tdmi;
const InstrFn = @import("../../cpu.zig").ArmInstrFn; const InstrFn = @import("../../cpu.zig").ArmInstrFn;
pub fn armSoftwareInterrupt() InstrFn { pub fn softwareInterrupt() InstrFn {
return struct { return struct {
fn inner(cpu: *Arm7tdmi, _: *Bus, _: u32) void { fn inner(cpu: *Arm7tdmi, _: *Bus, _: u32) void {
// Copy Values from Current Mode // Copy Values from Current Mode

54
src/cpu/thumb/branch.zig
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@ -1,54 +0,0 @@
const Bus = @import("../../Bus.zig");
const Arm7tdmi = @import("../../cpu.zig").Arm7tdmi;
const InstrFn = @import("../../cpu.zig").ThumbInstrFn;
const checkCond = @import("../../cpu.zig").checkCond;
const u32SignExtend = @import("../../util.zig").u32SignExtend;
pub fn format16(comptime cond: u4) InstrFn {
return struct {
fn inner(cpu: *Arm7tdmi, _: *Bus, opcode: u16) void {
// B
const offset = u32SignExtend(8, opcode & 0xFF) << 1;
const should_execute = switch (cond) {
0xE, 0xF => cpu.panic("[CPU/THUMB] Undefined conditional branch with condition {}", .{cond}),
else => checkCond(cpu.cpsr, cond),
};
if (should_execute) {
cpu.r[15] = (cpu.r[15] + 2) +% offset;
}
}
}.inner;
}
pub fn format18() InstrFn {
return struct {
// B but conditional
fn inner(cpu: *Arm7tdmi, _: *Bus, opcode: u16) void {
const offset = u32SignExtend(11, opcode & 0x7FF) << 1;
cpu.r[15] = (cpu.r[15] + 2) +% offset;
}
}.inner;
}
pub fn format19(comptime is_low: bool) InstrFn {
return struct {
fn inner(cpu: *Arm7tdmi, _: *Bus, opcode: u16) void {
// BL
const offset = opcode & 0x7FF;
if (is_low) {
// Instruction 2
const old_pc = cpu.r[15];
cpu.r[15] = cpu.r[14] + (offset << 1);
cpu.r[14] = old_pc | 1;
} else {
// Instruction 1
cpu.r[14] = (cpu.r[15] + 2) +% (u32SignExtend(11, @as(u32, offset)) << 12);
}
}
}.inner;
}

118
src/cpu/thumb/data_processing.zig
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@ -1,118 +0,0 @@
const Bus = @import("../../Bus.zig");
const Arm7tdmi = @import("../../cpu.zig").Arm7tdmi;
const InstrFn = @import("../../cpu.zig").ThumbInstrFn;
const shifter = @import("../barrel_shifter.zig");
const add = @import("../arm/data_processing.zig").add;
const sub = @import("../arm/data_processing.zig").sub;
const cmp = @import("../arm/data_processing.zig").cmp;
const setLogicOpFlags = @import("../arm/data_processing.zig").setLogicOpFlags;
pub fn format1(comptime op: u2, comptime offset: u5) InstrFn {
return struct {
fn inner(cpu: *Arm7tdmi, _: *Bus, opcode: u16) void {
const rs = opcode >> 3 & 0x7;
const rd = opcode & 0x7;
const result = switch (op) {
0b00 => blk: {
// LSL
if (offset == 0) {
break :blk cpu.r[rs];
} else {
break :blk shifter.logicalLeft(true, &cpu.cpsr, cpu.r[rs], offset);
}
},
0b01 => blk: {
// LSR
if (offset == 0) {
cpu.cpsr.c.write(cpu.r[rs] >> 31 & 1 == 1);
break :blk @as(u32, 0);
} else {
break :blk shifter.logicalRight(true, &cpu.cpsr, cpu.r[rs], offset);
}
},
0b10 => blk: {
// ASR
if (offset == 0) {
cpu.cpsr.c.write(cpu.r[rs] >> 31 & 1 == 1);
break :blk @bitCast(u32, @bitCast(i32, cpu.r[rs]) >> 31);
} else {
break :blk shifter.arithmeticRight(true, &cpu.cpsr, cpu.r[rs], offset);
}
},
else => cpu.panic("[CPU|THUMB|Fmt1] {} is an invalid op", .{op}),
};
// Equivalent to an ARM MOVS
cpu.r[rd] = result;
setLogicOpFlags(true, cpu, result);
}
}.inner;
}
pub fn format2(comptime I: bool, is_sub: bool, rn: u3) InstrFn {
return struct {
fn inner(cpu: *Arm7tdmi, _: *Bus, opcode: u16) void {
const rs = opcode >> 3 & 0x7;
const rd = @truncate(u3, opcode);
if (is_sub) {
// SUB
cpu.r[rd] = if (I) blk: {
break :blk sub(true, cpu, cpu.r[rs], @as(u32, rn));
} else blk: {
break :blk sub(true, cpu, cpu.r[rs], cpu.r[rn]);
};
} else {
// ADD
cpu.r[rd] = if (I) blk: {
break :blk add(true, cpu, cpu.r[rs], @as(u32, rn));
} else blk: {
break :blk add(true, cpu, cpu.r[rs], cpu.r[rn]);
};
}
}
}.inner;
}
pub fn format3(comptime op: u2, comptime rd: u3) InstrFn {
return struct {
fn inner(cpu: *Arm7tdmi, _: *Bus, opcode: u16) void {
const offset = @truncate(u8, opcode);
switch (op) {
0b00 => {
// MOV
cpu.r[rd] = offset;
setLogicOpFlags(true, cpu, offset);
},
0b01 => cmp(cpu, cpu.r[rd], offset), // CMP
0b10 => cpu.r[rd] = add(true, cpu, cpu.r[rd], offset), // ADD
0b11 => cpu.r[rd] = sub(true, cpu, cpu.r[rd], offset), // SUB
}
}
}.inner;
}
pub fn format12(comptime isSP: bool, comptime rd: u3) InstrFn {
return struct {
fn inner(cpu: *Arm7tdmi, _: *Bus, opcode: u16) void {
// ADD
const left = if (isSP) cpu.r[13] else (cpu.r[15] + 2) & 0xFFFF_FFFD;
const right = (opcode & 0xFF) << 2;
const result = left + right; // TODO: What about overflows?
cpu.r[rd] = result;
}
}.inner;
}
pub fn format13(comptime S: bool) InstrFn {
return struct {
fn inner(cpu: *Arm7tdmi, _: *Bus, opcode: u16) void {
// ADD
const offset = (opcode & 0x7F) << 2;
cpu.r[13] = if (S) cpu.r[13] - offset else cpu.r[13] + offset;
}
}.inner;
}

143
src/cpu/thumb/data_transfer.zig
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@ -1,143 +0,0 @@
const std = @import("std");
const Bus = @import("../../Bus.zig");
const Arm7tdmi = @import("../../cpu.zig").Arm7tdmi;
const InstrFn = @import("../../cpu.zig").ThumbInstrFn;
pub fn format6(comptime rd: u3) InstrFn {
return struct {
fn inner(cpu: *Arm7tdmi, bus: *Bus, opcode: u16) void {
// LDR
const offset = (opcode & 0xFF) << 2;
// FIXME: Should this overflow?
cpu.r[rd] = bus.read32((cpu.r[15] + 2 & 0xFFFF_FFFD) + offset);
}
}.inner;
}
const u32SignExtend = @import("../../util.zig").u32SignExtend;
pub fn format78(comptime op: u2, comptime T: bool) InstrFn {
return struct {
fn inner(cpu: *Arm7tdmi, bus: *Bus, opcode: u16) void {
const ro = opcode >> 6 & 0x7;
const rb = opcode >> 3 & 0x7;
const rd = opcode & 0x7;
const address = cpu.r[rb] + cpu.r[ro];
if (T) {
switch (op) {
0b00 => {
// STRH
bus.write16(address & 0xFFFF_FFFE, @truncate(u16, cpu.r[rd]));
},
0b01 => {
// LDRH
const value = bus.read16(address & 0xFFFF_FFFE);
cpu.r[rd] = std.math.rotr(u32, @as(u32, value), 8 * (address & 1));
},
0b10 => {
// LDSB
cpu.r[rd] = u32SignExtend(8, @as(u32, bus.read8(address)));
},
0b11 => {
// LDSH
cpu.r[rd] = u32SignExtend(16, @as(u32, bus.read16(address & 0xFFFF_FFFE)));
},
}
} else {
switch (op) {
0b00 => {
// STR
bus.write32(address & 0xFFFF_FFFC, cpu.r[rd]);
},
0b01 => {
// STRB
bus.write8(address, @truncate(u8, cpu.r[rd]));
},
0b10 => {
// LDR
const value = bus.read32(address & 0xFFFF_FFFC);
cpu.r[rd] = std.math.rotr(u32, value, 8 * (address & 0x3));
},
0b11 => {
// LDRB
cpu.r[rd] = bus.read8(address);
},
}
}
}
}.inner;
}
pub fn format9(comptime B: bool, comptime L: bool, comptime offset: u5) InstrFn {
return struct {
fn inner(cpu: *Arm7tdmi, bus: *Bus, opcode: u16) void {
const rb = opcode >> 3 & 0x7;
const rd = opcode & 0x7;
if (L) {
if (B) {
// LDRB
const address = cpu.r[rb] + offset;
cpu.r[rd] = bus.read8(address);
} else {
// LDR
const address = cpu.r[rb] + (@as(u32, offset) << 2);
const value = bus.read32(address & 0xFFFF_FFFC);
cpu.r[rd] = std.math.rotr(u32, value, 8 * (address & 0x3));
}
} else {
if (B) {
// STRB
const address = cpu.r[rb] + offset;
bus.write8(address, @truncate(u8, cpu.r[rd]));
} else {
// STR
const address = cpu.r[rb] + (@as(u32, offset) << 2);
bus.write32(address & 0xFFFF_FFFC, cpu.r[rd]);
}
}
}
}.inner;
}
pub fn format10(comptime L: bool, comptime offset: u5) InstrFn {
return struct {
fn inner(cpu: *Arm7tdmi, bus: *Bus, opcode: u16) void {
const rb = opcode >> 3 & 0x7;
const rd = opcode & 0x7;
const address = cpu.r[rb] + (offset << 1);
if (L) {
// LDRH
const value = bus.read16(address & 0xFFFF_FFFE);
cpu.r[rd] = std.math.rotr(u32, @as(u32, value), 8 * (address & 1));
} else {
// STRH
bus.write16(address & 0xFFFF_FFFE, @truncate(u16, cpu.r[rd]));
}
}
}.inner;
}
pub fn format11(comptime L: bool, comptime rd: u3) InstrFn {
return struct {
fn inner(cpu: *Arm7tdmi, bus: *Bus, opcode: u16) void {
const offset = (opcode & 0xFF) << 2;
const address = cpu.r[13] + offset;
if (L) {
// LDR
const value = bus.read32(address & 0xFFFF_FFFC);
cpu.r[rd] = std.math.rotr(u32, value, 8 * (address & 0x3));
} else {
// STR
bus.write32(address & 0xFFFF_FFFC, cpu.r[rd]);
}
}
}.inner;
}

51
src/cpu/thumb/format1.zig Normal file
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@ -0,0 +1,51 @@
const std = @import("std");
const Bus = @import("../../Bus.zig");
const Arm7tdmi = @import("../../cpu.zig").Arm7tdmi;
const InstrFn = @import("../../cpu.zig").ThumbInstrFn;
const shifter = @import("../barrel_shifter.zig");
const setLogicOpFlags = @import("../arm/data_processing.zig").setLogicOpFlags;
pub fn format1(comptime op: u2, comptime offset: u5) InstrFn {
return struct {
fn inner(cpu: *Arm7tdmi, _: *Bus, opcode: u16) void {
const rs = opcode >> 3 & 0x7;
const rd = opcode & 0x7;
const result = switch (op) {
0b00 => blk: {
// LSL
if (offset == 0) {
break :blk cpu.r[rs];
} else {
break :blk shifter.logicalLeft(true, &cpu.cpsr, cpu.r[rs], offset);
}
},
0b01 => blk: {
// LSR
if (offset == 0) {
cpu.cpsr.c.write(cpu.r[rs] >> 31 & 1 == 1);
break :blk @as(u32, 0);
} else {
break :blk shifter.logicalRight(true, &cpu.cpsr, cpu.r[rs], offset);
}
},
0b10 => blk: {
// ASR
if (offset == 0) {
cpu.cpsr.c.write(cpu.r[rs] >> 31 & 1 == 1);
break :blk @bitCast(u32, @bitCast(i32, cpu.r[rs]) >> 31);
} else {
break :blk shifter.arithmeticRight(true, &cpu.cpsr, cpu.r[rs], offset);
}
},
else => cpu.panic("[CPU|THUMB|Fmt1] {} is an invalid op", .{op}),
};
// Equivalent to an ARM MOVS
cpu.r[rd] = result;
setLogicOpFlags(true, cpu, result);
}
}.inner;
}

25
src/cpu/thumb/format10.zig Normal file
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@ -0,0 +1,25 @@
const std = @import("std");
const Bus = @import("../../Bus.zig");
const Arm7tdmi = @import("../../cpu.zig").Arm7tdmi;
const InstrFn = @import("../../cpu.zig").ThumbInstrFn;
pub fn format10(comptime L: bool, comptime offset: u5) InstrFn {
return struct {
fn inner(cpu: *Arm7tdmi, bus: *Bus, opcode: u16) void {
const rb = opcode >> 3 & 0x7;
const rd = opcode & 0x7;
const address = cpu.r[rb] + (offset << 1);
if (L) {
// LDRH
const value = bus.read16(address & 0xFFFF_FFFE);
cpu.r[rd] = std.math.rotr(u32, @as(u32, value), 8 * (address & 1));
} else {
// STRH
bus.write16(address & 0xFFFF_FFFE, @truncate(u16, cpu.r[rd]));
}
}
}.inner;
}

21
src/cpu/thumb/format11.zig Normal file
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@ -0,0 +1,21 @@
const std = @import("std");
const Bus = @import("../../Bus.zig");
const Arm7tdmi = @import("../../cpu.zig").Arm7tdmi;
const InstrFn = @import("../../cpu.zig").ThumbInstrFn;
pub fn format11(comptime L: bool, comptime rd: u3) InstrFn {
return struct {
fn inner(cpu: *Arm7tdmi, bus: *Bus, opcode: u16) void {
const offset = (opcode & 0xFF) << 2;
const address = cpu.r[13] + offset;
if (L) {
const value = bus.read32(address & 0xFFFF_FFFC);
cpu.r[rd] = std.math.rotr(u32, value, 8 * (address & 0x3));
} else {
bus.write32(address & 0xFFFF_FFFC, cpu.r[rd]);
}
}
}.inner;
}

17
src/cpu/thumb/format12.zig Normal file
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@ -0,0 +1,17 @@
const std = @import("std");
const Bus = @import("../../Bus.zig");
const Arm7tdmi = @import("../../cpu.zig").Arm7tdmi;
const InstrFn = @import("../../cpu.zig").ThumbInstrFn;
pub fn format12(comptime isSP: bool, comptime rd: u3) InstrFn {
return struct {
fn inner(cpu: *Arm7tdmi, _: *Bus, opcode: u16) void {
// ADD
const left = if (isSP) cpu.r[13] else (cpu.r[15] + 2) & 0xFFFF_FFFD;
const right = (opcode & 0xFF) << 2;
const result = left + right; // TODO: What about overflows?
cpu.r[rd] = result;
}
}.inner;
}

14
src/cpu/thumb/format13.zig Normal file
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@ -0,0 +1,14 @@
const std = @import("std");
const Bus = @import("../../Bus.zig");
const Arm7tdmi = @import("../../cpu.zig").Arm7tdmi;
const InstrFn = @import("../../cpu.zig").ThumbInstrFn;
pub fn format13(comptime S: bool) InstrFn {
return struct {
fn inner(cpu: *Arm7tdmi, _: *Bus, opcode: u16) void {
const offset = (opcode & 0x7F) << 2;
cpu.r[13] = if (S) cpu.r[13] - offset else cpu.r[13] + offset;
}
}.inner;
}

26
src/cpu/thumb/block_data_transfer.zig → src/cpu/thumb/format14.zig
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@ -1,3 +1,5 @@
const std = @import("std");
const Bus = @import("../../Bus.zig"); const Bus = @import("../../Bus.zig");
const Arm7tdmi = @import("../../cpu.zig").Arm7tdmi; const Arm7tdmi = @import("../../cpu.zig").Arm7tdmi;
const InstrFn = @import("../../cpu.zig").ThumbInstrFn; const InstrFn = @import("../../cpu.zig").ThumbInstrFn;
@ -46,27 +48,3 @@ pub fn format14(comptime L: bool, comptime R: bool) InstrFn {
} }
}.inner; }.inner;
} }
pub fn format15(comptime L: bool, comptime rb: u3) InstrFn {
return struct {
fn inner(cpu: *Arm7tdmi, bus: *Bus, opcode: u16) void {
const base = cpu.r[rb];
var address: u32 = base;
var i: usize = 0;
while (i < 8) : (i += 1) {
if ((opcode >> @truncate(u3, i)) & 1 == 1) {
if (L) {
cpu.r[i] = bus.read32(address);
} else {
bus.write32(address, cpu.r[i]);
}
address += 4;
}
}
cpu.r[rb] = address;
}
}.inner;
}

29
src/cpu/thumb/format15.zig Normal file
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@ -0,0 +1,29 @@
const std = @import("std");
const Bus = @import("../../Bus.zig");
const Arm7tdmi = @import("../../cpu.zig").Arm7tdmi;
const InstrFn = @import("../../cpu.zig").ThumbInstrFn;
pub fn format15(comptime L: bool, comptime rb: u3) InstrFn {
return struct {
fn inner(cpu: *Arm7tdmi, bus: *Bus, opcode: u16) void {
const base = cpu.r[rb];
var address: u32 = base;
var i: usize = 0;
while (i < 8) : (i += 1) {
if ((opcode >> @truncate(u3, i)) & 1 == 1) {
if (L) {
cpu.r[i] = bus.read32(address);
} else {
bus.write32(address, cpu.r[i]);
}
address += 4;
}
}
cpu.r[rb] = address;
}
}.inner;
}

26
src/cpu/thumb/format16.zig Normal file
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@ -0,0 +1,26 @@
const std = @import("std");
const Bus = @import("../../Bus.zig");
const Arm7tdmi = @import("../../cpu.zig").Arm7tdmi;
const InstrFn = @import("../../cpu.zig").ThumbInstrFn;
const checkCond = @import("../../cpu.zig").checkCond;
const u32SignExtend = @import("../../util.zig").u32SignExtend;
pub fn format16(comptime cond: u4) InstrFn {
return struct {
fn inner(cpu: *Arm7tdmi, _: *Bus, opcode: u16) void {
// B
const offset = u32SignExtend(8, opcode & 0xFF) << 1;
const should_execute = switch (cond) {
0xE, 0xF => cpu.panic("[CPU/THUMB] Undefined conditional branch with condition {}", .{cond}),
else => checkCond(cpu.cpsr, cond),
};
if (should_execute) {
cpu.r[15] = (cpu.r[15] + 2) +% offset;
}
}
}.inner;
}

4
src/cpu/thumb/software_interrupt.zig → src/cpu/thumb/format17.zig
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@ -1,8 +1,10 @@
const std = @import("std");
const Bus = @import("../../Bus.zig"); const Bus = @import("../../Bus.zig");
const Arm7tdmi = @import("../../cpu.zig").Arm7tdmi; const Arm7tdmi = @import("../../cpu.zig").Arm7tdmi;
const InstrFn = @import("../../cpu.zig").ThumbInstrFn; const InstrFn = @import("../../cpu.zig").ThumbInstrFn;
pub fn thumbSoftwareInterrupt() InstrFn { pub fn format17() InstrFn {
return struct { return struct {
fn inner(cpu: *Arm7tdmi, _: *Bus, _: u16) void { fn inner(cpu: *Arm7tdmi, _: *Bus, _: u16) void {
// Copy Values from Current Mode // Copy Values from Current Mode

15
src/cpu/thumb/format18.zig Normal file
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@ -0,0 +1,15 @@
const std = @import("std");
const Bus = @import("../../Bus.zig");
const Arm7tdmi = @import("../../cpu.zig").Arm7tdmi;
const InstrFn = @import("../../cpu.zig").ThumbInstrFn;
const u32SignExtend = @import("../../util.zig").u32SignExtend;
pub fn format18() InstrFn {
return struct {
fn inner(cpu: *Arm7tdmi, _: *Bus, opcode: u16) void {
const offset = u32SignExtend(11, opcode & 0x7FF) << 1;
cpu.r[15] = (cpu.r[15] + 2) +% offset;
}
}.inner;
}

26
src/cpu/thumb/format19.zig Normal file
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@ -0,0 +1,26 @@
const std = @import("std");
const Bus = @import("../../Bus.zig");
const Arm7tdmi = @import("../../cpu.zig").Arm7tdmi;
const InstrFn = @import("../../cpu.zig").ThumbInstrFn;
const u32SignExtend = @import("../../util.zig").u32SignExtend;
pub fn format19(comptime is_low: bool) InstrFn {
return struct {
fn inner(cpu: *Arm7tdmi, _: *Bus, opcode: u16) void {
// BL
const offset = opcode & 0x7FF;
if (is_low) {
// Instruction 2
const old_pc = cpu.r[15];
cpu.r[15] = cpu.r[14] + (offset << 1);
cpu.r[14] = old_pc | 1;
} else {
// Instruction 1
cpu.r[14] = (cpu.r[15] + 2) +% (u32SignExtend(11, @as(u32, offset)) << 12);
}
}
}.inner;
}

33
src/cpu/thumb/format2.zig Normal file
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@ -0,0 +1,33 @@
const std = @import("std");
const Bus = @import("../../Bus.zig");
const Arm7tdmi = @import("../../cpu.zig").Arm7tdmi;
const InstrFn = @import("../../cpu.zig").ThumbInstrFn;
const add = @import("../arm/data_processing.zig").add;
const sub = @import("../arm/data_processing.zig").sub;
pub fn format2(comptime I: bool, is_sub: bool, rn: u3) InstrFn {
return struct {
fn inner(cpu: *Arm7tdmi, _: *Bus, opcode: u16) void {
const rs = opcode >> 3 & 0x7;
const rd = @truncate(u3, opcode);
if (is_sub) {
// SUB
cpu.r[rd] = if (I) blk: {
break :blk sub(true, cpu, cpu.r[rs], @as(u32, rn));
} else blk: {
break :blk sub(true, cpu, cpu.r[rs], cpu.r[rn]);
};
} else {
// ADD
cpu.r[rd] = if (I) blk: {
break :blk add(true, cpu, cpu.r[rs], @as(u32, rn));
} else blk: {
break :blk add(true, cpu, cpu.r[rs], cpu.r[rn]);
};
}
}
}.inner;
}

29
src/cpu/thumb/format3.zig Normal file
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@ -0,0 +1,29 @@
const std = @import("std");
const Bus = @import("../../Bus.zig");
const Arm7tdmi = @import("../../cpu.zig").Arm7tdmi;
const InstrFn = @import("../../cpu.zig").ThumbInstrFn;
const add = @import("../arm/data_processing.zig").add;
const sub = @import("../arm/data_processing.zig").sub;
const cmp = @import("../arm/data_processing.zig").cmp;
const setLogicOpFlags = @import("../arm/data_processing.zig").setLogicOpFlags;
pub fn format3(comptime op: u2, comptime rd: u3) InstrFn {
return struct {
fn inner(cpu: *Arm7tdmi, _: *Bus, opcode: u16) void {
const offset = @truncate(u8, opcode);
switch (op) {
0b00 => {
// MOV
cpu.r[rd] = offset;
setLogicOpFlags(true, cpu, offset);
},
0b01 => cmp(cpu, cpu.r[rd], offset), // CMP
0b10 => cpu.r[rd] = add(true, cpu, cpu.r[rd], offset), // ADD
0b11 => cpu.r[rd] = sub(true, cpu, cpu.r[rd], offset), // SUB
}
}
}.inner;
}

0
src/cpu/thumb/alu.zig → src/cpu/thumb/format4.zig
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0
src/cpu/thumb/processing_branch.zig → src/cpu/thumb/format5.zig
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17
src/cpu/thumb/format6.zig Normal file
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@ -0,0 +1,17 @@
const std = @import("std");
const Bus = @import("../../Bus.zig");
const Arm7tdmi = @import("../../cpu.zig").Arm7tdmi;
const InstrFn = @import("../../cpu.zig").ThumbInstrFn;
pub fn format6(comptime rd: u3) InstrFn {
return struct {
fn inner(cpu: *Arm7tdmi, bus: *Bus, opcode: u16) void {
// LDR
const offset = (opcode & 0xFF) << 2;
// FIXME: Should this overflow?
cpu.r[rd] = bus.read32((cpu.r[15] + 2 & 0xFFFF_FFFD) + offset);
}
}.inner;
}

60
src/cpu/thumb/format78.zig Normal file
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@ -0,0 +1,60 @@
const std = @import("std");
const Bus = @import("../../Bus.zig");
const Arm7tdmi = @import("../../cpu.zig").Arm7tdmi;
const InstrFn = @import("../../cpu.zig").ThumbInstrFn;
const u32SignExtend = @import("../../util.zig").u32SignExtend;
pub fn format78(comptime op: u2, comptime T: bool) InstrFn {
return struct {
fn inner(cpu: *Arm7tdmi, bus: *Bus, opcode: u16) void {
const ro = opcode >> 6 & 0x7;
const rb = opcode >> 3 & 0x7;
const rd = opcode & 0x7;
const address = cpu.r[rb] + cpu.r[ro];
if (T) {
switch (op) {
0b00 => {
// STRH
bus.write16(address & 0xFFFF_FFFE, @truncate(u16, cpu.r[rd]));
},
0b01 => {
// LDRH
const value = bus.read16(address & 0xFFFF_FFFE);
cpu.r[rd] = std.math.rotr(u32, @as(u32, value), 8 * (address & 1));
},
0b10 => {
// LDSB
cpu.r[rd] = u32SignExtend(8, @as(u32, bus.read8(address)));
},
0b11 => {
// LDSH
cpu.r[rd] = u32SignExtend(16, @as(u32, bus.read16(address & 0xFFFF_FFFE)));
},
}
} else {
switch (op) {
0b00 => {
// STR
bus.write32(address & 0xFFFF_FFFC, cpu.r[rd]);
},
0b01 => {
// STRB
bus.write8(address, @truncate(u8, cpu.r[rd]));
},
0b10 => {
// LDR
const value = bus.read32(address & 0xFFFF_FFFC);
cpu.r[rd] = std.math.rotr(u32, value, 8 * (address & 0x3));
},
0b11 => {
// LDRB
cpu.r[rd] = bus.read8(address);
},
}
}
}
}.inner;
}

37
src/cpu/thumb/format9.zig Normal file
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@ -0,0 +1,37 @@
const std = @import("std");
const Bus = @import("../../Bus.zig");
const Arm7tdmi = @import("../../cpu.zig").Arm7tdmi;
const InstrFn = @import("../../cpu.zig").ThumbInstrFn;
pub fn format9(comptime B: bool, comptime L: bool, comptime offset: u5) InstrFn {
return struct {
fn inner(cpu: *Arm7tdmi, bus: *Bus, opcode: u16) void {
const rb = opcode >> 3 & 0x7;
const rd = opcode & 0x7;
if (L) {
if (B) {
// LDRB
const address = cpu.r[rb] + offset;
cpu.r[rd] = bus.read8(address);
} else {
// LDR
const address = cpu.r[rb] + (@as(u32, offset) << 2);
const value = bus.read32(address & 0xFFFF_FFFC);
cpu.r[rd] = std.math.rotr(u32, value, 8 * (address & 0x3));
}
} else {
if (B) {
// STRB
const address = cpu.r[rb] + offset;
bus.write8(address, @truncate(u8, cpu.r[rd]));
} else {
// STR
const address = cpu.r[rb] + (@as(u32, offset) << 2);
bus.write32(address & 0xFFFF_FFFC, cpu.r[rd]);
}
}
}
}.inner;
}