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Fix word alignment for arm BX

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Former-commit-id: 9223259793cd8ecccb02b40c428d32315c632bff
This commit is contained in:
Michel Heily 2019-07-10 21:44:48 +03:00
parent 2864f83681
commit 50086a8715
2 changed files with 11 additions and 18 deletions
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15
src/arm7tdmi/arm/exec.rs
View file

@ -44,20 +44,25 @@ impl Core {
Ok(CpuPipelineAction::Flush) Ok(CpuPipelineAction::Flush)
} }
/// Cycles 2S+1N pub fn branch_exchange(&mut self, mut addr: Addr) -> CpuResult<CpuPipelineAction> {
fn exec_bx(&mut self, _bus: &mut Bus, insn: ArmInstruction) -> CpuResult<CpuPipelineAction> { if addr.bit(0) {
let rn = self.get_reg(insn.rn()); addr = addr & !0x1;
if rn.bit(0) {
self.cpsr.set_state(CpuState::THUMB); self.cpsr.set_state(CpuState::THUMB);
} else { } else {
addr = addr & !0x3;
self.cpsr.set_state(CpuState::ARM); self.cpsr.set_state(CpuState::ARM);
} }
self.pc = rn & !1; self.pc = addr;
Ok(CpuPipelineAction::Flush) Ok(CpuPipelineAction::Flush)
} }
/// Cycles 2S+1N
fn exec_bx(&mut self, _bus: &mut Bus, insn: ArmInstruction) -> CpuResult<CpuPipelineAction> {
self.branch_exchange(self.get_reg(insn.rn()))
}
fn exec_swi(&mut self, _bus: &mut Bus, _insn: ArmInstruction) -> CpuResult<CpuPipelineAction> { fn exec_swi(&mut self, _bus: &mut Bus, _insn: ArmInstruction) -> CpuResult<CpuPipelineAction> {
self.exception(Exception::SoftwareInterrupt); self.exception(Exception::SoftwareInterrupt);
Ok(CpuPipelineAction::Flush) Ok(CpuPipelineAction::Flush)

14
src/arm7tdmi/thumb/exec.rs
View file

@ -112,19 +112,7 @@ impl Core {
} else { } else {
insn.rs() insn.rs()
}; };
self.branch_exchange(self.get_reg(src_reg))
let mut addr = self.get_reg(src_reg);
if addr.bit(0) {
self.cpsr.set_state(CpuState::THUMB);
} else {
// word align when switching to arm state
addr = addr & !0x3;
self.cpsr.set_state(CpuState::ARM);
}
self.pc = addr & !1;
Ok(CpuPipelineAction::Flush)
} }
fn exec_thumb_hi_reg_op_or_bx( fn exec_thumb_hi_reg_op_or_bx(