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43
src/arm/cpu/arm/half_signed_data_transfer.zig
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@ -17,11 +17,9 @@ pub fn halfAndSignedDataTransfer(comptime InstrFn: type, comptime P: bool, compt
const modified_base = if (U) base +% offset else base -% offset; const modified_base = if (U) base +% offset else base -% offset;
var address = if (P) modified_base else base; var address = if (P) modified_base else base;
const op: u2 = @truncate(opcode >> 5);
var result: u32 = undefined; var result: u32 = undefined;
if (L) { if (L) {
switch (op) { switch (@as(u2, @truncate(opcode >> 5))) {
0b01 => { 0b01 => {
// LDRH // LDRH
const value = cpu.read(u16, address); const value = cpu.read(u16, address);
@ -38,46 +36,15 @@ pub fn halfAndSignedDataTransfer(comptime InstrFn: type, comptime P: bool, compt
// FIXME: I shouldn't have to use @as(u8, ...) here // FIXME: I shouldn't have to use @as(u8, ...) here
result = if (address & 1 == 1) sext(u32, u8, @as(u8, @truncate(value >> 8))) else sext(u32, u16, value); result = if (address & 1 == 1) sext(u32, u8, @as(u8, @truncate(value >> 8))) else sext(u32, u16, value);
}, },
0b00 => unreachable, // SWP / SWPB dealt with in single_data_swap.zig 0b00 => unreachable, // SWP
} }
} else { } else {
switch (op) { if (opcode >> 5 & 0x01 == 0x01) {
0b01 => {
// STRH // STRH
// FIXME: I shouldn't have to use @as(u16, ...) here // FIXME: I shouldn't have to use @as(u8, ...) here
cpu.write(u16, address, @as(u16, @truncate(cpu.r[rd]))); cpu.write(u16, address, @as(u16, @truncate(cpu.r[rd])));
}, } else unreachable; // SWP
0b10 => {
// LDRD
if (Arm32.arch != .v5te) cpu.panic("LDRD: unsupported on arm{s}", .{@tagName(Arm32.arch)});
if (rd & 0 != 0) cpu.panic("LDRD: UNDEFINED behaviour when Rd is not even", .{});
if (rd == 0xE) cpu.panic("LDRD: UNPREDICTABLE behaviour when rd == 14", .{});
if (address & 0x7 != 0b000) cpu.panic("LDRD: UNPREDICTABLE when address (0x{X:0>8} is not double (64-bit) aligned", .{address});
// Why do we not make use of result here?
//
// It's because L is not set so there's no chance of writing an undefined
// value to the register
//
// despite this reason, this is bad design imo
// TODO: Refactor this handler
cpu.r[rd] = cpu.read(u32, address);
cpu.r[rd + 1] = cpu.read(u32, address + 4);
},
0b11 => {
// STRD
if (Arm32.arch != .v5te) cpu.panic("STRD: unsupported on arm{s}", .{@tagName(Arm32.arch)});
if (rd & 0 != 0) cpu.panic("STRD: UNDEFINED behaviour when Rd is not even", .{});
if (rd == 0xE) cpu.panic("STRD: UNPREDICTABLE behaviour when rd == 14", .{});
if (address & 0x7 != 0b000) cpu.panic("STRD: UNPREDICTABLE when address (0x{X:0>8} is not double (64-bit) aligned", .{address});
cpu.write(u32, address, cpu.r[rd]);
cpu.write(u32, address + 4, cpu.r[rd + 1]);
},
else => unreachable,
}
} }
address = modified_base; address = modified_base;

17
src/arm/cpu/arm/misc_instructions.zig
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@ -1,17 +0,0 @@
const sext = @import("zba-util").sext;
pub fn clz(comptime InstrFn: type) InstrFn {
const Arm32 = @typeInfo(@typeInfo(@typeInfo(InstrFn).Pointer.child).Fn.params[0].type.?).Pointer.child;
return struct {
pub fn inner(cpu: *Arm32, opcode: u32) void {
const rd = opcode >> 12 & 0xF;
const rm = opcode & 0xF;
if (rd == 0xF) cpu.panic("CLZ: UNPREDICTABLE behaviour when rd == 15", .{});
if (rm == 0xF) cpu.panic("CLZ: UNPREDICTABLE behaviour when rm == 15", .{});
cpu.r[rd] = @clz(cpu.r[rm]);
}
}.inner;
}

38
src/arm/cpu/arm/multiply.zig
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@ -1,4 +1,4 @@
pub fn multiply(comptime InstrFn: type, comptime L: bool, comptime U: bool, comptime A: bool, comptime S: bool) InstrFn { pub fn multiply(comptime InstrFn: type, comptime A: bool, comptime S: bool) InstrFn {
const Arm32 = @typeInfo(@typeInfo(@typeInfo(InstrFn).Pointer.child).Fn.params[0].type.?).Pointer.child; const Arm32 = @typeInfo(@typeInfo(@typeInfo(InstrFn).Pointer.child).Fn.params[0].type.?).Pointer.child;
return struct { return struct {
@ -8,9 +8,28 @@ pub fn multiply(comptime InstrFn: type, comptime L: bool, comptime U: bool, comp
const rs = opcode >> 8 & 0xF; const rs = opcode >> 8 & 0xF;
const rm = opcode & 0xF; const rm = opcode & 0xF;
if (L) { const temp: u64 = @as(u64, cpu.r[rm]) * @as(u64, cpu.r[rs]) + if (A) cpu.r[rn] else 0;
const rd_hi = rd; const result: u32 = @truncate(temp);
const rd_lo = rn; cpu.r[rd] = result;
if (S) {
cpu.cpsr.n.write(result >> 31 & 1 == 1);
cpu.cpsr.z.write(result == 0);
// V is unaffected, C is *actually* undefined in ARMv4
}
}
}.inner;
}
pub fn multiplyLong(comptime InstrFn: type, comptime U: bool, comptime A: bool, comptime S: bool) InstrFn {
const Arm32 = @typeInfo(@typeInfo(@typeInfo(InstrFn).Pointer.child).Fn.params[0].type.?).Pointer.child;
return struct {
fn inner(cpu: *Arm32, 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) { if (U) {
// Signed (WHY IS IT U THEN?) // Signed (WHY IS IT U THEN?)
@ -33,17 +52,6 @@ pub fn multiply(comptime InstrFn: type, comptime L: bool, comptime U: bool, comp
cpu.cpsr.n.write(cpu.r[rd_hi] >> 31 & 1 == 1); cpu.cpsr.n.write(cpu.r[rd_hi] >> 31 & 1 == 1);
// C and V are set to meaningless values // C and V are set to meaningless values
} }
} else {
const temp: u64 = @as(u64, cpu.r[rm]) * @as(u64, cpu.r[rs]) + if (A) cpu.r[rn] else 0;
const result: u32 = @truncate(temp);
cpu.r[rd] = result;
if (S) {
cpu.cpsr.n.write(result >> 31 & 1 == 1);
cpu.cpsr.z.write(result == 0);
// V is unaffected, C is *actually* undefined in ARMv4
}
}
} }
}.inner; }.inner;
} }

38
src/arm/cpu/arm/psr_transfer.zig
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@ -1,42 +1,29 @@
const std = @import("std"); const std = @import("std");
const rotr = @import("zba-util").rotr;
const PSR = @import("../../../arm.zig").PSR; const PSR = @import("../../../arm.zig").PSR;
const log = std.log.scoped(.ctrl_ext_space); const log = std.log.scoped(.PsrTransfer);
pub fn control(comptime InstrFn: type, comptime I: bool, comptime op: u6) InstrFn { const rotr = @import("zba-util").rotr;
pub fn psrTransfer(comptime InstrFn: type, comptime I: bool, comptime R: bool, comptime kind: u2) InstrFn {
const Arm32 = @typeInfo(@typeInfo(@typeInfo(InstrFn).Pointer.child).Fn.params[0].type.?).Pointer.child; const Arm32 = @typeInfo(@typeInfo(@typeInfo(InstrFn).Pointer.child).Fn.params[0].type.?).Pointer.child;
return struct { return struct {
fn inner(cpu: *Arm32, opcode: u32) void { fn inner(cpu: *Arm32, opcode: u32) void {
if (I) { switch (kind) {
// MSR (register) 0b00 => {
const R = op >> 5 & 1 == 1; // MRS
msr(R, I, cpu, opcode);
return;
}
switch (op) {
0b00_0000, 0b10_0000 => { // MRS
const R = op >> 5 & 1 == 1;
const rd = opcode >> 12 & 0xF; const rd = opcode >> 12 & 0xF;
if (R and !cpu.hasSPSR()) log.err("Tried to read SPSR from User/System Mode", .{}); if (R and !cpu.hasSPSR()) log.err("Tried to read SPSR from User/System Mode", .{});
cpu.r[rd] = if (R) cpu.spsr.raw else cpu.cpsr.raw; cpu.r[rd] = if (R) cpu.spsr.raw else cpu.cpsr.raw;
}, },
0b01_0000, 0b11_0000 => { // MSR (register) 0b10 => {
const R = op >> 5 & 1 == 1; // MSR
msr(R, false, cpu, opcode);
},
else => cpu.panic("unhandled instruction: 0x{X:0>8}", .{opcode}),
}
}
inline fn msr(comptime R: bool, comptime imm: bool, cpu: *Arm32, opcode: u32) void {
const field_mask: u4 = @truncate(opcode >> 16 & 0xF); const field_mask: u4 = @truncate(opcode >> 16 & 0xF);
const rm_idx = opcode & 0xF; const rm_idx = opcode & 0xF;
const right = if (imm) rotr(u32, opcode & 0xFF, (opcode >> 8 & 0xF) * 2) else cpu.r[rm_idx]; const right = if (I) rotr(u32, opcode & 0xFF, (opcode >> 8 & 0xF) * 2) else cpu.r[rm_idx];
if (R and !cpu.hasSPSR()) log.err("Tried to write to SPSR in User/System Mode", .{}); if (R and !cpu.hasSPSR()) log.err("Tried to write to SPSR in User/System Mode", .{});
@ -48,6 +35,9 @@ pub fn control(comptime InstrFn: type, comptime I: bool, comptime op: u6) InstrF
} else { } else {
if (cpu.isPrivileged()) cpu.setCpsr(fieldMask(&cpu.cpsr, field_mask, right)); if (cpu.isPrivileged()) cpu.setCpsr(fieldMask(&cpu.cpsr, field_mask, right));
} }
},
else => cpu.panic("[CPU/PSR Transfer] Bits 21:220 of {X:0>8} are undefined", .{opcode}),
}
} }
}.inner; }.inner;
} }

21
src/arm/v4t.zig
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@ -5,6 +5,7 @@ pub const arm = struct {
pub const lut: [0x1000]InstrFn = populate(); pub const lut: [0x1000]InstrFn = populate();
const processing = @import("cpu/arm/data_processing.zig").dataProcessing; const processing = @import("cpu/arm/data_processing.zig").dataProcessing;
const psrTransfer = @import("cpu/arm/psr_transfer.zig").psrTransfer;
const transfer = @import("cpu/arm/single_data_transfer.zig").singleDataTransfer; const transfer = @import("cpu/arm/single_data_transfer.zig").singleDataTransfer;
const halfSignedTransfer = @import("cpu/arm/half_signed_data_transfer.zig").halfAndSignedDataTransfer; const halfSignedTransfer = @import("cpu/arm/half_signed_data_transfer.zig").halfAndSignedDataTransfer;
const blockTransfer = @import("cpu/arm/block_data_transfer.zig").blockDataTransfer; const blockTransfer = @import("cpu/arm/block_data_transfer.zig").blockDataTransfer;
@ -13,11 +14,8 @@ pub const arm = struct {
const swi = @import("cpu/arm/software_interrupt.zig").armSoftwareInterrupt; const swi = @import("cpu/arm/software_interrupt.zig").armSoftwareInterrupt;
const swap = @import("cpu/arm/single_data_swap.zig").singleDataSwap; const swap = @import("cpu/arm/single_data_swap.zig").singleDataSwap;
// Control Instruction Extension Space
const control = @import("cpu/arm/psr_transfer.zig").control;
/// Arithmetic Instruction Extension Space
const multiply = @import("cpu/arm/multiply.zig").multiply; const multiply = @import("cpu/arm/multiply.zig").multiply;
const multiplyLong = @import("cpu/arm/multiply.zig").multiplyLong;
/// Determine index into ARM InstrFn LUT /// Determine index into ARM InstrFn LUT
pub fn idx(opcode: u32) u12 { pub fn idx(opcode: u32) u12 {
@ -40,15 +38,18 @@ pub const arm = struct {
handler.* = switch (@as(u2, i >> 10)) { handler.* = switch (@as(u2, i >> 10)) {
0b00 => if (i == 0x121) blk: { 0b00 => if (i == 0x121) blk: {
break :blk branchExchange(InstrFn); break :blk branchExchange(InstrFn);
} else if (i & 0xFCF == 0x009) blk: {
const A = i >> 5 & 1 == 1;
const S = i >> 4 & 1 == 1;
break :blk multiply(InstrFn, A, S);
} else if (i & 0xFBF == 0x109) blk: { } else if (i & 0xFBF == 0x109) blk: {
const B = i >> 6 & 1 == 1; const B = i >> 6 & 1 == 1;
break :blk swap(InstrFn, B); break :blk swap(InstrFn, B);
} else if (i & 0xF0F == 0x009) blk: { } else if (i & 0xF8F == 0x089) blk: {
const L = i >> 7 & 1 == 1;
const U = i >> 6 & 1 == 1; const U = i >> 6 & 1 == 1;
const A = i >> 5 & 1 == 1; const A = i >> 5 & 1 == 1;
const S = i >> 4 & 1 == 1; const S = i >> 4 & 1 == 1;
break :blk multiply(InstrFn, L, U, A, S); break :blk multiplyLong(InstrFn, U, A, S);
} else if (i & 0xE49 == 0x009 or i & 0xE49 == 0x049) blk: { } else if (i & 0xE49 == 0x009 or i & 0xE49 == 0x049) blk: {
const P = i >> 8 & 1 == 1; const P = i >> 8 & 1 == 1;
const U = i >> 7 & 1 == 1; const U = i >> 7 & 1 == 1;
@ -58,9 +59,9 @@ pub const arm = struct {
break :blk halfSignedTransfer(InstrFn, P, U, I, W, L); break :blk halfSignedTransfer(InstrFn, P, U, I, W, L);
} else if (i & 0xD90 == 0x100) blk: { } else if (i & 0xD90 == 0x100) blk: {
const I = i >> 9 & 1 == 1; const I = i >> 9 & 1 == 1;
const op = ((i >> 5) & 0x3) << 4 | (i & 0xF); const R = i >> 6 & 1 == 1;
const kind = i >> 4 & 0x3;
break :blk control(InstrFn, I, op); break :blk psrTransfer(InstrFn, I, R, kind);
} else blk: { } else blk: {
const I = i >> 9 & 1 == 1; const I = i >> 9 & 1 == 1;
const S = i >> 4 & 1 == 1; const S = i >> 4 & 1 == 1;

31
src/arm/v5te.zig
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@ -5,6 +5,7 @@ pub const arm = struct {
pub const lut: [0x1000]InstrFn = populate(); pub const lut: [0x1000]InstrFn = populate();
const processing = @import("cpu/arm/data_processing.zig").dataProcessing; const processing = @import("cpu/arm/data_processing.zig").dataProcessing;
const psrTransfer = @import("cpu/arm/psr_transfer.zig").psrTransfer;
const transfer = @import("cpu/arm/single_data_transfer.zig").singleDataTransfer; const transfer = @import("cpu/arm/single_data_transfer.zig").singleDataTransfer;
const halfSignedTransfer = @import("cpu/arm/half_signed_data_transfer.zig").halfAndSignedDataTransfer; const halfSignedTransfer = @import("cpu/arm/half_signed_data_transfer.zig").halfAndSignedDataTransfer;
const blockTransfer = @import("cpu/arm/block_data_transfer.zig").blockDataTransfer; const blockTransfer = @import("cpu/arm/block_data_transfer.zig").blockDataTransfer;
@ -13,14 +14,10 @@ pub const arm = struct {
const swi = @import("cpu/arm/software_interrupt.zig").armSoftwareInterrupt; const swi = @import("cpu/arm/software_interrupt.zig").armSoftwareInterrupt;
const swap = @import("cpu/arm/single_data_swap.zig").singleDataSwap; const swap = @import("cpu/arm/single_data_swap.zig").singleDataSwap;
// Control Instruction Extension Space
const control = @import("cpu/arm/psr_transfer.zig").control;
// Arithmetic Instruction Extension Space
const multiply = @import("cpu/arm/multiply.zig").multiply; const multiply = @import("cpu/arm/multiply.zig").multiply;
const multiplyLong = @import("cpu/arm/multiply.zig").multiplyLong;
const cop = @import("cpu/arm/coprocessor.zig"); const cop = @import("cpu/arm/coprocessor.zig");
const clz = @import("cpu/arm/misc_instructions.zig").clz;
/// Determine index into ARM InstrFn LUT /// Determine index into ARM InstrFn LUT
pub fn idx(opcode: u32) u12 { pub fn idx(opcode: u32) u12 {
@ -41,30 +38,32 @@ pub const arm = struct {
for (&table, 0..) |*handler, i| { for (&table, 0..) |*handler, i| {
handler.* = switch (@as(u2, i >> 10)) { handler.* = switch (@as(u2, i >> 10)) {
0b00 => if (i == 0x121) blk: { // 12 bits 0b00 => if (i == 0x121) blk: {
break :blk branchExchange(InstrFn); break :blk branchExchange(InstrFn);
} else if (i == 0x161) blk: { // 12 bits } else if (i & 0xFCF == 0x009) blk: {
break :blk clz(InstrFn); const A = i >> 5 & 1 == 1;
} else if (i & 0xFBF == 0x109) blk: { // 11 bits const S = i >> 4 & 1 == 1;
break :blk multiply(InstrFn, A, S);
} else if (i & 0xFBF == 0x109) blk: {
const B = i >> 6 & 1 == 1; const B = i >> 6 & 1 == 1;
break :blk swap(InstrFn, B); break :blk swap(InstrFn, B);
} else if (i & 0xF0F == 0x009) blk: { // 8 bits } else if (i & 0xF8F == 0x089) blk: {
const L = i >> 7 & 1 == 1;
const U = i >> 6 & 1 == 1; const U = i >> 6 & 1 == 1;
const A = i >> 5 & 1 == 1; const A = i >> 5 & 1 == 1;
const S = i >> 4 & 1 == 1; const S = i >> 4 & 1 == 1;
break :blk multiply(InstrFn, L, U, A, S); break :blk multiplyLong(InstrFn, U, A, S);
} else if (i & 0xE49 == 0x009 or i & 0xE49 == 0x049) blk: { // 6 bits } else if (i & 0xE49 == 0x009 or i & 0xE49 == 0x049) blk: {
const P = i >> 8 & 1 == 1; const P = i >> 8 & 1 == 1;
const U = i >> 7 & 1 == 1; const U = i >> 7 & 1 == 1;
const I = i >> 6 & 1 == 1; const I = i >> 6 & 1 == 1;
const W = i >> 5 & 1 == 1; const W = i >> 5 & 1 == 1;
const L = i >> 4 & 1 == 1; const L = i >> 4 & 1 == 1;
break :blk halfSignedTransfer(InstrFn, P, U, I, W, L); break :blk halfSignedTransfer(InstrFn, P, U, I, W, L);
} else if (i & 0xD90 == 0x100) blk: { // 6 bits } else if (i & 0xD90 == 0x100) blk: {
const I = i >> 9 & 1 == 1; const I = i >> 9 & 1 == 1;
const op = ((i >> 5) & 0x3) << 4 | (i & 0xF); const R = i >> 6 & 1 == 1;
break :blk control(InstrFn, I, op); const kind = i >> 4 & 0x3;
break :blk psrTransfer(InstrFn, I, R, kind);
} else blk: { } else blk: {
const I = i >> 9 & 1 == 1; const I = i >> 9 & 1 == 1;
const S = i >> 4 & 1 == 1; const S = i >> 4 & 1 == 1;