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Avoid phoney write modifies.

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This commit is contained in:
Thomas Harte 2022-05-27 21:42:55 -04:00
parent 0e6370d467
commit 1365fca161
1 changed files with 3 additions and 6 deletions
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9
Machines/Apple/Macintosh/Macintosh.cpp
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@ -236,20 +236,18 @@ template <Analyser::Static::Macintosh::Target::Model model> class ConcreteMachin
// which at word precision is 0x77f0ff + register*256.
if(cycle.operation & Microcycle::Read) {
cycle.value->b = via_.read(register_address);
if(cycle.operation & Microcycle::SelectWord) cycle.value->w |= 0xff00;
} else {
via_.write(register_address, cycle.value->b);
}
if(cycle.operation & Microcycle::SelectWord) cycle.value->w |= 0xff00;
}
} return delay;
case BusDevice::PhaseRead: {
if(cycle.operation & Microcycle::Read) {
cycle.value->b = phase_ & 7;
if(cycle.operation & Microcycle::SelectWord) cycle.value->w |= 0xff00;
}
if(cycle.operation & Microcycle::SelectWord) cycle.value->w |= 0xff00;
} return delay;
case BusDevice::IWM: {
@ -259,11 +257,10 @@ template <Analyser::Static::Macintosh::Target::Model model> class ConcreteMachin
// The IWM; this is a purely polled device, so can be run on demand.
if(cycle.operation & Microcycle::Read) {
cycle.value->b = iwm_->read(register_address);
if(cycle.operation & Microcycle::SelectWord) cycle.value->w |= 0xff00;
} else {
iwm_->write(register_address, cycle.value->b);
}
if(cycle.operation & Microcycle::SelectWord) cycle.value->w |= 0xff00;
} else {
fill_unmapped(cycle);
}