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changed initial stack pointer to 0xff in tests 

fixed pop_word_from_stack
This commit is contained in:
jborza 2019-04-26 11:24:49 +02:00
parent 047efec29c
commit eb1134b0da
1 changed files with 3 additions and 4 deletions
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7
cpu.c
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@ -47,7 +47,7 @@ void clear_state(State6502 * state) {
state->x = 0;
state->y = 0;
state->pc = 0;
state->sp = 0;
state->sp = 0xFF;
clear_flags(state);
state->running = 1;
}
@ -73,7 +73,7 @@ byte pop_byte_from_stack(State6502 * state) {
word pop_word_from_stack(State6502* state) {
byte low = pop_byte_from_stack(state);
byte high = pop_byte_from_stack(state);
return low + (high >> 8);
return low + ((word)high >> 8);
}
//bitwise or with accumulator
@ -266,12 +266,11 @@ void ROR_MEM(State6502 * state, word address) {
}
void JSR(State6502 * state, word address) {
byte target = state->memory[address];
//JSR pushes the address-1 of the next operation on to the stack before transferring program control to the following address.
word address_to_push = state->pc - 1;
push_byte_to_stack(state, (address_to_push >> 8 & 0xFF));
push_byte_to_stack(state, address_to_push & 0xFF);
state->pc = target;
state->pc = address;
}
void RTS_(State6502* state) {