From d9039db73aafe9d5743528357c258d8d207d0f12 Mon Sep 17 00:00:00 2001
From: leo <leo@azuminha.com>
Date: Sun, 8 Oct 2023 19:41:11 -0300
Subject: Primeiro opcode, CPU

---
 CPU.c | 69 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 69 insertions(+)
 create mode 100644 CPU.c

diff --git a/CPU.c b/CPU.c
new file mode 100644
index 0000000..cf95cbd
--- /dev/null
+++ b/CPU.c
@@ -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");
+}
\ No newline at end of file
-- 
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