diff --git a/src/core/cpu.zig b/src/core/cpu.zig index d77b68d..a0b2717 100644 --- a/src/core/cpu.zig +++ b/src/core/cpu.zig @@ -323,21 +323,8 @@ pub const Arm7tdmi = struct { return self.bus.io.haltcnt == .Halt; } - pub fn setCpsrNoFlush(self: *Self, value: u32) void { - if (value & 0x1F != self.cpsr.raw & 0x1F) self.changeModeFromIdx(@truncate(u5, value & 0x1F)); - self.cpsr.raw = value; - } - pub fn setCpsr(self: *Self, value: u32) void { if (value & 0x1F != self.cpsr.raw & 0x1F) self.changeModeFromIdx(@truncate(u5, value & 0x1F)); - - const new: PSR = .{ .raw = value }; - if (self.cpsr.t.read() != new.t.read()) { - // If THUMB to ARM or ARM to THUMB, flush pipeline - self.r[15] &= if (new.t.read()) ~@as(u32, 1) else ~@as(u32, 3); - if (new.t.read()) self.pipe.reload(u16, self) else self.pipe.reload(u32, self); - } - self.cpsr.raw = value; } @@ -500,7 +487,8 @@ pub const Arm7tdmi = struct { // log.debug("Handling Interrupt!", .{}); self.bus.io.haltcnt = .Execute; - const ret_addr = self.r[15] - if (self.cpsr.t.read()) 2 else @as(u32, 4); + // FIXME: This seems weird, but retAddr.gba suggests I need to make these changes + const ret_addr = self.r[15] - if (self.cpsr.t.read()) 0 else @as(u32, 4); const new_spsr = self.cpsr.raw; self.changeMode(.Irq); @@ -510,7 +498,7 @@ pub const Arm7tdmi = struct { self.r[14] = ret_addr; self.spsr.raw = new_spsr; self.r[15] = 0x0000_0018; - self.pipe.reload(u32, self); + self.pipe.reload(self); } inline fn fetch(self: *Self, comptime T: type) T { @@ -692,18 +680,17 @@ const Pipline = struct { return opcode; } - pub fn reload(self: *Self, comptime T: type, cpu: *Arm7tdmi) void { - comptime std.debug.assert(T == u32 or T == u16); + pub fn reload(self: *Self, cpu: *Arm7tdmi) void { + if (cpu.cpsr.t.read()) { + self.stage[0] = cpu.bus.read(u16, cpu.r[15]); + self.stage[1] = cpu.bus.read(u16, cpu.r[15] + 2); + cpu.r[15] += 4; + } else { + self.stage[0] = cpu.bus.read(u32, cpu.r[15]); + self.stage[1] = cpu.bus.read(u32, cpu.r[15] + 4); + cpu.r[15] += 8; + } - // Sometimes, the pipeline can be reloaded twice in the same instruction - // This can happen if: - // 1. R15 is written to - // 2. The CPSR is written to (and T changes), so R15 is written to again - - self.stage[0] = cpu.bus.read(T, cpu.r[15]); - self.stage[1] = cpu.bus.read(T, cpu.r[15] + if (T == u32) 4 else @as(u32, 2)); - - cpu.r[15] += if (T == u32) 8 else @as(u32, 4); self.flushed = true; } }; diff --git a/src/core/cpu/arm/block_data_transfer.zig b/src/core/cpu/arm/block_data_transfer.zig index 32aafba..f94cbf9 100644 --- a/src/core/cpu/arm/block_data_transfer.zig +++ b/src/core/cpu/arm/block_data_transfer.zig @@ -55,7 +55,7 @@ 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.reload(u32, cpu); + cpu.pipe.reload(cpu); } else { // FIXME: Should r15 on write be +12 ahead? bus.write(u32, und_addr, cpu.r[15] + 4); @@ -92,7 +92,7 @@ pub fn blockDataTransfer(comptime P: bool, comptime U: bool, comptime S: bool, c cpu.r[i] = value; if (i == 0xF) { cpu.r[i] &= ~@as(u32, 3); // Align r15 - cpu.pipe.reload(u32, cpu); + cpu.pipe.reload(cpu); if (S) cpu.setCpsr(cpu.spsr.raw); } diff --git a/src/core/cpu/arm/branch.zig b/src/core/cpu/arm/branch.zig index 368735a..c4f9594 100644 --- a/src/core/cpu/arm/branch.zig +++ b/src/core/cpu/arm/branch.zig @@ -12,7 +12,7 @@ pub fn branch(comptime L: bool) InstrFn { if (L) cpu.r[14] = cpu.r[15] - 4; cpu.r[15] +%= sext(u32, u24, opcode) << 2; - cpu.pipe.reload(u32, cpu); + cpu.pipe.reload(cpu); } }.inner; } @@ -24,5 +24,5 @@ pub fn branchAndExchange(cpu: *Arm7tdmi, _: *Bus, opcode: u32) void { cpu.r[15] = cpu.r[rn] & if (thumb) ~@as(u32, 1) else ~@as(u32, 3); cpu.cpsr.t.write(thumb); - if (thumb) cpu.pipe.reload(u16, cpu) else cpu.pipe.reload(u32, cpu); + cpu.pipe.reload(cpu); } diff --git a/src/core/cpu/arm/data_processing.zig b/src/core/cpu/arm/data_processing.zig index 604921c..65df83f 100644 --- a/src/core/cpu/arm/data_processing.zig +++ b/src/core/cpu/arm/data_processing.zig @@ -76,9 +76,8 @@ pub fn dataProcessing(comptime I: bool, comptime S: bool, comptime kind: u4) Ins else => { cpu.r[rd] = result; if (rd == 0xF) { - if (S) cpu.setCpsrNoFlush(cpu.spsr.raw); - - cpu.pipe.reload(u32, cpu); + if (S) cpu.setCpsr(cpu.spsr.raw); + cpu.pipe.reload(cpu); } }, } @@ -180,5 +179,5 @@ pub fn adc(overflow: *bool, left: u32, right: u32, old_carry: u1) u32 { fn undefinedTestBehaviour(cpu: *Arm7tdmi) void { @setCold(true); - cpu.setCpsrNoFlush(cpu.spsr.raw); + cpu.setCpsr(cpu.spsr.raw); } diff --git a/src/core/cpu/arm/single_data_transfer.zig b/src/core/cpu/arm/single_data_transfer.zig index 091e151..fcab5d7 100644 --- a/src/core/cpu/arm/single_data_transfer.zig +++ b/src/core/cpu/arm/single_data_transfer.zig @@ -47,13 +47,13 @@ pub fn singleDataTransfer(comptime I: bool, comptime P: bool, comptime U: bool, address = modified_base; if (W and P or !P) { cpu.r[rn] = address; - if (rn == 0xF) cpu.pipe.reload(u32, cpu); + if (rn == 0xF) cpu.pipe.reload(cpu); } if (L) { // This emulates the LDR rd == rn behaviour cpu.r[rd] = result; - if (rd == 0xF) cpu.pipe.reload(u32, cpu); + if (rd == 0xF) cpu.pipe.reload(cpu); } } }.inner; diff --git a/src/core/cpu/arm/software_interrupt.zig b/src/core/cpu/arm/software_interrupt.zig index 50f6674..b44cf99 100644 --- a/src/core/cpu/arm/software_interrupt.zig +++ b/src/core/cpu/arm/software_interrupt.zig @@ -17,7 +17,7 @@ pub fn armSoftwareInterrupt() InstrFn { cpu.r[14] = ret_addr; // Resume Execution cpu.spsr.raw = cpsr; // Previous mode CPSR cpu.r[15] = 0x0000_0008; - cpu.pipe.reload(u32, cpu); + cpu.pipe.reload(cpu); } }.inner; } diff --git a/src/core/cpu/thumb/block_data_transfer.zig b/src/core/cpu/thumb/block_data_transfer.zig index 2f3b2a3..014729f 100644 --- a/src/core/cpu/thumb/block_data_transfer.zig +++ b/src/core/cpu/thumb/block_data_transfer.zig @@ -34,7 +34,7 @@ pub fn fmt14(comptime L: bool, comptime R: bool) InstrFn { if (L) { const value = bus.read(u32, address); cpu.r[15] = value & ~@as(u32, 1); - cpu.pipe.reload(u16, cpu); + cpu.pipe.reload(cpu); } else { bus.write(u32, address, cpu.r[14]); } @@ -55,7 +55,7 @@ pub fn fmt15(comptime L: bool, comptime rb: u3) InstrFn { if (opcode & 0xFF == 0) { if (L) { cpu.r[15] = bus.read(u32, address); - cpu.pipe.reload(u16, cpu); + cpu.pipe.reload(cpu); } else { bus.write(u32, address, cpu.r[15] + 2); } diff --git a/src/core/cpu/thumb/branch.zig b/src/core/cpu/thumb/branch.zig index 4c8a076..4d00577 100644 --- a/src/core/cpu/thumb/branch.zig +++ b/src/core/cpu/thumb/branch.zig @@ -15,7 +15,7 @@ pub fn fmt16(comptime cond: u4) InstrFn { if (!checkCond(cpu.cpsr, cond)) return; cpu.r[15] +%= sext(u32, u8, opcode & 0xFF) << 1; - cpu.pipe.reload(u16, cpu); + cpu.pipe.reload(cpu); } }.inner; } @@ -25,7 +25,7 @@ pub fn fmt18() InstrFn { // B but conditional fn inner(cpu: *Arm7tdmi, _: *Bus, opcode: u16) void { cpu.r[15] +%= sext(u32, u11, opcode & 0x7FF) << 1; - cpu.pipe.reload(u16, cpu); + cpu.pipe.reload(cpu); } }.inner; } @@ -43,7 +43,7 @@ pub fn fmt19(comptime is_low: bool) InstrFn { cpu.r[15] = cpu.r[14] +% (offset << 1); cpu.r[14] = next_opcode | 1; - cpu.pipe.reload(u16, cpu); + cpu.pipe.reload(cpu); } else { // Instruction 1 const lr_offset = sext(u32, u11, offset) << 12; diff --git a/src/core/cpu/thumb/data_processing.zig b/src/core/cpu/thumb/data_processing.zig index e0e6c50..bd27f48 100644 --- a/src/core/cpu/thumb/data_processing.zig +++ b/src/core/cpu/thumb/data_processing.zig @@ -83,13 +83,13 @@ pub fn fmt5(comptime op: u2, comptime h1: u1, comptime h2: u1) InstrFn { cpu.r[15] = op2 & ~@as(u32, 1); cpu.cpsr.t.write(is_thumb); - if (is_thumb) cpu.pipe.reload(u16, cpu) else cpu.pipe.reload(u32, cpu); + cpu.pipe.reload(cpu); }, else => { cpu.r[rd] = result; if (rd == 0xF) { cpu.r[15] &= ~@as(u32, 1); - cpu.pipe.reload(u16, cpu); + cpu.pipe.reload(cpu); } }, } diff --git a/src/core/cpu/thumb/software_interrupt.zig b/src/core/cpu/thumb/software_interrupt.zig index 96806d2..893f902 100644 --- a/src/core/cpu/thumb/software_interrupt.zig +++ b/src/core/cpu/thumb/software_interrupt.zig @@ -17,7 +17,7 @@ pub fn fmt17() InstrFn { cpu.r[14] = ret_addr; // Resume Execution cpu.spsr.raw = cpsr; // Previous mode CPSR cpu.r[15] = 0x0000_0008; - cpu.pipe.reload(u32, cpu); + cpu.pipe.reload(cpu); } }.inner; }