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fixed INTCXROM loading/handling. Added comments in updateMemoryPages() as the functionality was verified.

This commit is contained in:
Jorj Bauer 2017-02-28 23:34:24 -05:00
parent 080b236ab2
commit 609e5456b2
1 changed files with 20 additions and 12 deletions
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32
apple/applemmu.cpp
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@ -683,12 +683,13 @@ void AppleMMU::resetRAM()
uint8_t v = romData[idx];
#endif
for (int j=0; j<5; j++) {
// FIXME: not sure why this has to update pages [0] and [1] to
// work; find out what the //e really did
for (uint8_t j=0; j<2; j++) {
if (ramPages[i][j]) {
ramPages[i][j][k] = v;
}
// For the ROM section from 0xc100 .. 0xcfff, we load in to
// an alternate page space (INTCXROM).
if (i >= 0xc1 && i <= 0xcf) {
ramPages[i][1][k] = v;
} else {
// Everything else goes in page 0.
ramPages[i][0][k] = v;
}
}
}
@ -759,12 +760,22 @@ void AppleMMU::updateMemoryPages()
}
if (switches & S_80STORE) {
// When S_80STORE is on, we switch 400-800 and 2000-4000 based on S_PAGE2.
// The behavior is different based on whether HIRESON/OFF is set.
if (switches & S_PAGE2) {
// Regardless of HIRESON/OFF, pages 0x400-0x7ff are switched on S_PAGE2
for (uint8_t idx = 0x04; idx < 0x08; idx++) {
readPages[idx] = ramPages[idx][1];
writePages[idx] = ramPages[idx][1];
}
// but 2000-3fff switches based on S_PAGE2 only if HIRES is on.
// HIRESOFF: 400-7ff doesn't switch based on read/write flags
// b/c it switches based on S_PAGE2 instead
// HIRESON: 400-800, 2000-3fff doesn't switch
// b/c they switch based on S_PAGE2 instead
// If HIRES is on, then we honor the PAGE2 setting; otherwise, we don't
for (uint8_t idx = 0x20; idx < 0x40; idx++) {
readPages[idx] = ramPages[idx][(switches & S_HIRES) ? 1 : 0];
@ -775,12 +786,9 @@ void AppleMMU::updateMemoryPages()
readPages[idx] = ramPages[idx][0];
writePages[idx] = ramPages[idx][0];
}
if (switches & S_HIRES) {
// PAGE2 is off, so we set this back to 0 regardless
for (uint8_t idx = 0x20; idx < 0x40; idx++) {
readPages[idx] = ramPages[idx][0];
writePages[idx] = ramPages[idx][0];
}
for (uint8_t idx = 0x20; idx < 0x40; idx++) {
readPages[idx] = ramPages[idx][0];
writePages[idx] = ramPages[idx][0];
}
}
}