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bus: separate out read/write that count cycles

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Signed-off-by: Amneesh Singh <natto@weirdnatto.in>
This commit is contained in:
Amneesh Singh
2024-06-19 14:53:31 +05:30
parent f5aa73e7ca
commit 7d3996526f
9 changed files with 262 additions and 282 deletions
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24
src/cpu/cpu.cc
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@@ -132,7 +132,7 @@ Cpu::step() {
arm::Instruction instruction(opcodes[0]);
opcodes[0] = opcodes[1];
opcodes[1] = bus->read_word(pc, sequential);
opcodes[1] = bus->read_word(pc, next_access);
#ifdef DISASSEMBLER
glogger.info("0x{:08X} : {}",
@@ -151,7 +151,7 @@ Cpu::step() {
thumb::Instruction instruction(opcodes[0]);
opcodes[0] = opcodes[1];
opcodes[1] = bus->read_halfword(pc, sequential);
opcodes[1] = bus->read_halfword(pc, next_access);
#ifdef DISASSEMBLER
glogger.info("0x{:08X} : {}",
@@ -168,4 +168,24 @@ Cpu::step() {
advance_pc_thumb();
}
}
void
Cpu::flush_pipeline() {
// halfword align
rst_bit(pc, 0);
if (cpsr.state() == State::Arm) {
// word align
rst_bit(pc, 1);
opcodes[0] = bus->read_word(pc, CpuAccess::NonSequential);
advance_pc_arm();
opcodes[1] = bus->read_word(pc, CpuAccess::Sequential);
advance_pc_arm();
} else {
opcodes[0] = bus->read_halfword(pc, CpuAccess::NonSequential);
advance_pc_thumb();
opcodes[1] = bus->read_halfword(pc, CpuAccess::Sequential);
advance_pc_thumb();
}
next_access = CpuAccess::Sequential;
};
}