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Slightly simplifies bus decoding.

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This commit is contained in:
Thomas Harte 2018-04-08 18:51:37 -04:00
parent cf6f6c5c15
commit 94b1c37fb2
1 changed files with 10 additions and 6 deletions
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16
Machines/Commodore/Vic-20/Vic20.cpp
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@ -546,12 +546,12 @@ class ConcreteMachine:
if(isReadOperation(operation)) {
uint8_t result = processor_read_memory_map_[address >> 10] ? processor_read_memory_map_[address >> 10][address & 0x3ff] : 0xff;
if((address&0xfc00) == 0x9000) {
if((address&0xff00) == 0x9000) {
if(!(address&0x100)) {
update_video();
result &= mos6560_->get_register(address);
}
if((address&0xfc10) == 0x9010) result &= user_port_via_.get_register(address);
if((address&0xfc20) == 0x9020) result &= keyboard_via_.get_register(address);
if(address & 0x10) result &= user_port_via_.get_register(address);
if(address & 0x20) result &= keyboard_via_.get_register(address);
}
*value = result;
@ -630,13 +630,17 @@ class ConcreteMachine:
update_video();
ram[address & 0x3ff] = *value;
}
// Anything between 0x9000 and 0x9400 is the IO area.
if((address&0xfc00) == 0x9000) {
if((address&0xff00) == 0x9000) {
// The VIC is selected by bit 8 = 0
if(!(address&0x100)) {
update_video();
mos6560_->set_register(address, *value);
}
if((address&0xfc10) == 0x9010) user_port_via_.set_register(address, *value);
if((address&0xfc20) == 0x9020) keyboard_via_.set_register(address, *value);
// The first VIA is selected by bit 4 = 1.
if(address & 0x10) user_port_via_.set_register(address, *value);
// The second VIA is selected by bit 5 = 1.
if(address & 0x20) keyboard_via_.set_register(address, *value);
}
}