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Added the capacity to back-date interrupt line changes within a machine cycle, so that machines which time themselves entirely within perform_machine_cycle can still be cycle accurate on those changes.

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Thomas Harte 2017-06-11 13:31:02 -04:00
parent 50be3a24fe
commit db30f53ab0
1 changed files with 21 additions and 3 deletions
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24
Processors/Z80/Z80.hpp
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@ -1734,8 +1734,12 @@ template <class T> class Processor {
/*!
Sets the logical value of the interrupt line.
@param offset If called while within perform_machine_cycle this may be a value indicating
how many cycles before now the line changed state. The value may not be longer than the
current machine cycle. If called at any other time, this must be zero.
*/
void set_interrupt_line(bool value) {
void set_interrupt_line(bool value, int offset = 0) {
if(irq_line_ == value) return;
// IRQ requests are level triggered and masked.
@ -1745,14 +1749,28 @@ template <class T> class Processor {
} else {
request_status_ &= ~Interrupt::IRQ;
}
// If this change happened at least one cycle ago then: (i) we're promised that this is a machine
// cycle per the contract on supplying an offset; and (ii) that means it happened before the lines
// were sampled. So adjust the most recent sample.
if(offset <= 0) {
last_request_status_ = (last_request_status_ & ~Interrupt::IRQ) | (request_status_ & Interrupt::IRQ);
}
}
/*!
Sets the logical value of the non-maskable interrupt line.
@param offset See discussion in set_interrupt_line.
*/
void set_non_maskable_interrupt_line(bool value) {
void set_non_maskable_interrupt_line(bool value, int offset = 0) {
// NMIs are edge triggered and cannot be masked.
if(value) request_status_ |= Interrupt::NMI;
if(value) {
request_status_ |= Interrupt::NMI;
if(offset <= 0) {
last_request_status_ |= Interrupt::NMI;
}
}
}
/*!