diff options
| -rw-r--r-- | CPU.c | 69 |
1 files changed, 69 insertions, 0 deletions
@@ -0,0 +1,69 @@ +#include <stdlib.h> +#include <stdint.h> +#include <stdio.h> +#include <assert.h> + +struct CPU{ + uint8_t register_a; + uint8_t status; + uint16_t pc; +}; + +struct CPU create_cpu(){ + struct CPU cpu = { + .register_a = 0, + .status = 0, + .pc = 0 + }; + return cpu; +} + +void interpret(struct CPU *cpu, uint8_t *program){ + cpu->pc = 0; + + while(1){ + uint8_t opcode = program[cpu->pc]; + cpu->pc += 1; + + switch(opcode){ + case 0x00: + return; + case 0xA9: + uint8_t param = program[cpu->pc]; + cpu->pc += 1; + cpu->register_a = param; + + if(cpu->register_a == 0) + cpu->status |= 0b00000010; + else + cpu->status &= 0b11111101; + + if((cpu->register_a & 0b10000000) != 0) + cpu->status |= 0b10000000; + else + cpu->status &= 0b01111111; + default: + break; + } + } + + return; +} + +int main(){ + printf("test_0xa9_lda_immediate_load_data: "); + struct CPU cpu_1 = create_cpu(); + uint8_t program_1[] = {0xa9, 0x05, 0x00}; + interpret(&cpu_1, program_1); + assert(cpu_1.register_a == 0x05); + assert((cpu_1.status & 0b00000010) == 0b00); + assert((cpu_1.status & 0b10000000) == 0); + printf("PASSED\n"); + + printf("test_0xa9_lda_zero_flag: "); + struct CPU cpu_2 = create_cpu(); + uint8_t program_2[] = {0xa9, 0x00, 0x00}; + interpret(&cpu_2, program_2); + assert((cpu_2.status & 0b00000010) == 0b00000010); + printf("PASSED\n"); +}
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