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Implements STP and WAI.

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Albeit still without fully-implemented reactions to exceptions in general.
This commit is contained in:
Thomas Harte 2020-10-11 17:56:55 -04:00
parent 8eaf1303a3
commit a0885ab7d0
3 changed files with 38 additions and 15 deletions
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27
Processors/65816/Implementation/65816Implementation.hpp
View File

@ -170,6 +170,19 @@ template <typename BusHandler> void Processor<BusHandler>::run_for(const Cycles
#undef stack_access
//
// STP and WAI.
//
case CycleRepeatingNone:
if(pending_exceptions_ & required_exceptions_) {
continue;
} else {
--next_op_;
perform_bus(0xffffff, nullptr, MOS6502Esque::None);
}
break;
//
// Data movement.
//
@ -822,11 +835,17 @@ template <typename BusHandler> void Processor<BusHandler>::run_for(const Cycles
LD(a_, result, m_masks_);
} break;
// TODO:
// STP, WAI,
//
// STP and WAI
//
default:
assert(false);
case STP:
required_exceptions_ = Reset;
break;
case WAI:
required_exceptions_ = Reset | IRQ | NMI;
break;
}
continue;
}

19
Processors/65816/Implementation/65816Storage.cpp
View File

@ -539,18 +539,15 @@ struct CPU::WDC65816::ProcessorStorageConstructor {
target(OperationPerform);
}
// 19c. Stop the Clock.
static void stp(AccessType, bool, const std::function<void(MicroOp)> &target) {
target(CycleFetchPCThrowaway); // IO
target(CycleFetchPCThrowaway); // IO
target(OperationPerform);
}
// 19c. Stop the Clock; also
// 19d. Wait for interrupt.
static void wai(AccessType, bool, const std::function<void(MicroOp)> &target) {
static void stp_wai(AccessType, bool, const std::function<void(MicroOp)> &target) {
target(OperationPerform); // Establishes the termination condition.
target(CycleFetchPCThrowaway); // IO
target(CycleFetchPCThrowaway); // IO
target(OperationPerform);
target(CycleRepeatingNone); // This will first check whether the STP/WAI exit
// condition has occurred; if not then it'll issue
// a BusOperation::None and then reschedule itself.
}
// 20. Relative; r.
@ -955,7 +952,7 @@ ProcessorStorage::ProcessorStorage() {
/* 0xc8 INY i */ op(implied, INY);
/* 0xc9 CMP # */ op(immediate, CMP);
/* 0xca DEX i */ op(implied, DEX);
/* 0xcb WAI i */ op(wai, WAI);
/* 0xcb WAI i */ op(stp_wai, WAI);
/* 0xcc CPY a */ op(absolute, CPY);
/* 0xcd CMP a */ op(absolute, CMP);
/* 0xce DEC a */ op(absolute_rmw, DEC);
@ -972,7 +969,7 @@ ProcessorStorage::ProcessorStorage() {
/* 0xd8 CLD i */ op(implied, CLD);
/* 0xd9 CMP a, y */ op(absolute_y, CMP);
/* 0xda PHX s */ op(stack_push, STX);
/* 0xdb STP i */ op(stp, STP);
/* 0xdb STP i */ op(stp_wai, STP);
/* 0xdc JML (a) */ op(absolute_indirect_jml, JML);
/* 0xdd CMP a, x */ op(absolute_x, CMP);
/* 0xde DEC a, x */ op(absolute_x_rmw, DEC);

7
Processors/65816/Implementation/65816Storage.hpp
View File

@ -47,6 +47,10 @@ enum MicroOp: uint8_t {
/// Performs as CyclePull if the 65816 is not in emulation mode; otherwise skips itself.
CyclePullIfNotEmulation,
/// Issues a BusOperation::None and regresses the micro-op counter until an established
/// STP or WAI condition is satisfied.
CycleRepeatingNone,
/// Sets the data address by copying the final two bytes of the instruction buffer and
/// using the data register as a high byte.
OperationConstructAbsolute,
@ -261,6 +265,9 @@ struct ProcessorStorage {
static constexpr int NMI = 1 << 3;
int pending_exceptions_ = PowerOn; // By default.
/// Sets the required exception flags necessary to exit a STP or WAI.
int required_exceptions_ = 0;
/// Defines a four-byte buffer which can be cleared or filled in single-byte increments from least significant byte
/// to most significant.
struct Buffer {