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Succeeds at executing a single instruction.

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This commit is contained in:
Thomas Harte 2021-01-18 20:16:01 -05:00
parent e71e506883
commit c78c121159
3 changed files with 20 additions and 7 deletions
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4
InstructionSets/CachingExecutor.hpp
View File

@ -95,10 +95,6 @@ template <
// indexed by array position, which is a lot more compact than a generic pointer.
std::array<Performer, max_performer_count> performers_;
// TODO: should I include a program counter at all? Are there platforms
// for which the expense of retaining opcode length doesn't buy any benefit?
ProgramCounterType program_counter_;
/*!
Moves the current point of execution to @c address, updating necessary performer caches

20
InstructionSets/M50740/Executor.cpp
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@ -10,6 +10,7 @@
#include <algorithm>
#include <cassert>
#include <cstring>
using namespace InstructionSet::M50740;
@ -144,7 +145,20 @@ template <Operation operation, AddressingMode addressing_mode> void Executor::pe
}
template <Operation operation> void Executor::perform(uint8_t *operand [[maybe_unused]]) {
// switch(operation) {
// default: assert(false);
// }
switch(operation) {
case Operation::LDA: a_ = *operand; break; // TODO: flags (for all three here).
case Operation::LDX: x_ = *operand; break;
case Operation::LDY: y_ = *operand; break;
case Operation::STA: *operand = a_; break;
case Operation::STX: *operand = x_; break;
case Operation::STY: *operand = y_; break;
default: assert(false);
}
}
void Executor::set_program_counter(uint16_t address) {
program_counter_ = address;
CachingExecutor::set_program_counter(address);
}

3
InstructionSets/M50740/Executor.hpp
View File

@ -100,6 +100,8 @@ class Executor: public CachingExecutor {
*/
template <Operation operation, AddressingMode addressing_mode> void perform();
void set_program_counter(uint16_t address);
private:
// MARK: - Instruction set state.
@ -107,6 +109,7 @@ class Executor: public CachingExecutor {
uint8_t memory_[0x2000];
// Registers.
uint16_t program_counter_;
uint8_t a_, x_, y_;
};