diff --git a/src/cpu.zig b/src/cpu.zig index 5ec9559..432c646 100644 --- a/src/cpu.zig +++ b/src/cpu.zig @@ -418,9 +418,10 @@ pub const Arm7tdmi = struct { if (self.cpsr.t.read()) { if (opcode >> 11 == 0x1E) { // Instruction 1 of a BL Opcode, print in ARM mode - const tmp_opcode = self.bus.read(u32, self.r[15] - 2); - const be_opcode = tmp_opcode << 16 | tmp_opcode >> 16; - log_str = try std.fmt.bufPrint(&buf, arm_fmt, .{ r0, r1, r2, r3, r4, r5, r6, r7, r8, r9, r10, r11, r12, r13, r14, r15, c_psr, be_opcode }); + const other_half = self.bus.debugRead(u16, self.r[15]); + const bl_opcode = @as(u32, opcode) << 16 | other_half; + + log_str = try std.fmt.bufPrint(&buf, arm_fmt, .{ r0, r1, r2, r3, r4, r5, r6, r7, r8, r9, r10, r11, r12, r13, r14, r15, c_psr, bl_opcode }); } else { log_str = try std.fmt.bufPrint(&buf, thumb_fmt, .{ r0, r1, r2, r3, r4, r5, r6, r7, r8, r9, r10, r11, r12, r13, r14, r15, c_psr, opcode }); } diff --git a/src/cpu/arm/branch.zig b/src/cpu/arm/branch.zig index 362366a..03b4fd5 100644 --- a/src/cpu/arm/branch.zig +++ b/src/cpu/arm/branch.zig @@ -10,7 +10,7 @@ pub fn branch(comptime L: bool) InstrFn { return struct { fn inner(cpu: *Arm7tdmi, _: *Bus, opcode: u32) void { if (L) cpu.r[14] = cpu.r[15]; - cpu.r[15] = cpu.fakePC() +% sext(24, opcode << 2); + cpu.r[15] = cpu.fakePC() +% (sext(24, opcode) << 2); } }.inner; }