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attempted to fix flag handling of PLP

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This commit is contained in:
jborza 2019-05-01 22:59:15 +02:00
parent 5ae9274ab9
commit de70338f49
2 changed files with 29 additions and 2 deletions
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3
cpu.c
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@ -344,6 +344,8 @@ void PLP_(State6502* state) {
byte value = pop_byte_from_stack(state);
//we don't read the BRK flag
value &= ~(1 << 4);
//the bit 5 always comes in as true
value |= 1 << 5;
memset(&state->flags, value, sizeof(Flags));
}
@ -353,7 +355,6 @@ void PHP_(State6502* state) {
push_byte_to_stack(state, flags_value);
}
int emulate_6502_op(State6502 * state) {
byte* opcode = &state->memory[state->pc++];
switch (*opcode) {

28
test6502.c
View File

@ -1987,7 +1987,33 @@ void test_PLP2() {
assert_flag_z(&state, 0);
assert_flag_v(&state, 0);
assert_flag_n(&state, 0);
assert_flag_i(&state, 0);
assert_flag_i(&state, 1);
//cleanup
test_cleanup(&state);
}
void test_PHA_PLP() {
State6502 state = create_blank_state();
//arrange
char program[] = { LDA_IMM, 0x04, PHA, PLP };
memcpy(state.memory, program, sizeof(program));
//act
test_step(&state);
assertA(&state, 0x04);
//assert
assert_sp(&state, 0xFF);
assert_flag_c(&state, 0);
assert_flag_d(&state, 0);
assert_flag_b(&state, 0);
assert_flag_z(&state, 0);
assert_flag_v(&state, 0);
assert_flag_n(&state, 0);
assert_flag_i(&state, 1);
//cleanup
test_cleanup(&state);