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MMR1 locking

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folkert van heusden 2024-04-12 22:43:35 +02:00
parent 616674f8b1
commit 773d2f4e94
Signed by untrusted user who does not match committer: folkert
GPG key ID: 6B6455EDFEED3BD1
2 changed files with 9 additions and 6 deletions
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1
bus.h
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@ -170,6 +170,7 @@ public:
uint16_t getMMR2() { return MMR2; }
uint16_t getMMR3() { return MMR3; }
uint16_t getMMR(int nr) { uint16_t *mmrs[] { &MMR0, &MMR1, &MMR2, &MMR3 }; return *mmrs[nr]; }
bool isMMR1Locked() { return !!(getMMR0() & 0160000); }
void clearMMR1();
void addToMMR1(const int8_t delta, const uint8_t reg);
void setMMR0(const uint16_t value);

10
cpu.cpp
View file

@ -365,7 +365,7 @@ void cpu::queue_interrupt(const uint8_t level, const uint8_t vector)
void cpu::addToMMR1(const gam_rc_t & g)
{
if (g.mmr1_update.has_value()) {
if (!b->isMMR1Locked() && g.mmr1_update.has_value()) {
assert(g.mmr1_update.value().delta);
b->addToMMR1(g.mmr1_update.value().delta, g.mmr1_update.value().reg);
@ -1644,9 +1644,11 @@ bool cpu::misc_operations(const uint16_t instr)
// PUSH link
pushStack(getRegister(link_reg));
if (!b->isMMR1Locked()) {
b->addToMMR1(-2, 6);
addToMMR1(a);
}
// MOVE PC,link
setRegister(link_reg, getPC());
@ -2253,11 +2255,11 @@ void cpu::step_a()
{
it_is_a_trap = false;
if ((b->getMMR0() & 0160000) == 0)
if (!b->isMMR1Locked())
b->clearMMR1();
if (any_queued_interrupts && check_queued_interrupts()) {
if ((b->getMMR0() & 0160000) == 0)
if (!b->isMMR1Locked())
b->clearMMR1();
}
}
@ -2269,7 +2271,7 @@ void cpu::step_b()
try {
uint16_t temp_pc = getPC();
if ((b->getMMR0() & 0160000) == 0)
if (!b->isMMR1Locked())
b->setMMR2(temp_pc);
uint16_t instr = b->readWord(temp_pc);