Added tests for all the ALU operations, although lacking the full imp…

…lementations of the ALU flags.

emulator/src/components.c

@@ -34,7 +34,7 @@ static word_t rotl(word_t a, word_t n) { return (a << n) | (a >> (sizeof(word_t)
  */
 word_t alu(ALUOperation op, word_t a, word_t b, uint8_t *flags) {
 
- word_t result;
+ word_t result = 0;
  *flags = 0;
 
  switch (op) {
@@ -61,7 +61,10 @@ word_t alu(ALUOperation op, word_t a, word_t b, uint8_t *flags) {
  result = a * b;
  break;
  case ALU_DIV:
- result = a / b;
+ if (b == 0)
+ result = 0;
+ else
+ result = a / b;
  break;
  case ALU_LSL:
  result = a << b;
@@ -76,12 +79,11 @@ word_t alu(ALUOperation op, word_t a, word_t b, uint8_t *flags) {
  result = rotr(a, b);
  break;
  case ALU_NOOP:
- result = 0;
  break;
  }
 
  // TODO implement flags for all operations
- if (result == 0) *flags |= (0xFF & FLAG_ZERO);
+ if (result == 0 && op != ALU_NOOP) *flags |= (0xFF & FLAG_ZERO);
  if (result & 0x8000) *flags |= (0xFF & FLAG_NEGATIVE);
 
  return result;

emulator/tests/main.c

@@ -1,8 +1,10 @@
 #include "../src/components.h"
 #include <assert.h>
+#include <stdint.h>
 #include <stdio.h>
 
 static void test_alu_add(void) {
+ // TODO revisit when carry and overflow are added
  uint8_t flags;
 
  assert(alu(ALU_ADD, 1, 3, &flags) == 4);
@@ -16,6 +18,20 @@ static void test_alu_add(void) {
  assert(flags & FLAG_NEGATIVE);
 }
 
+static void test_alu_sub(void) {
+ // TODO revisit when carry and overflow are added
+ uint8_t flags;
+
+ assert(alu(ALU_SUB, 5, 1, &flags) == 4);
+ assert(flags == 0);
+
+ assert(alu(ALU_SUB, 1, 1, &flags) == 0);
+ assert(flags & FLAG_ZERO);
+
+ assert(alu(ALU_SUB, 1, 2, &flags) == 0xFFFF);
+ assert(flags & FLAG_NEGATIVE);
+}
+
 static void test_alu_and(void) {
  uint8_t flags;
 
@@ -69,6 +85,7 @@ static void test_alu_rb(void) {
 }
 
 static void test_alu_mul(void) {
+ // TODO revisit when carry and overflow are added
  uint8_t flags;
 
  assert(alu(ALU_MUL, 5, 5, &flags) == 25);
@@ -84,6 +101,23 @@ static void test_alu_mul(void) {
  assert(flags == 0);
 }
 
+static void test_alu_div(void) {
+ // TODO revisit when carry and overflow are added
+ uint8_t flags;
+
+ assert(alu(ALU_DIV, 5, 5, &flags) == 1);
+ assert(flags == 0);
+
+ assert(alu(ALU_DIV, 0, 10, &flags) == 0);
+ assert(flags & FLAG_ZERO);
+
+ assert(alu(ALU_DIV, 1, 0, &flags) == 0);
+ assert(flags & FLAG_ZERO);
+
+ assert(alu(ALU_DIV, 0xFFFF, 13107, &flags) == 5);
+ assert(flags == 0);
+}
+
 static void test_alu_lsl(void) {
  uint8_t flags;
 
@@ -97,18 +131,79 @@ static void test_alu_lsl(void) {
  assert(flags & FLAG_NEGATIVE);
 }
 
+static void test_alu_lsr(void) {
+ uint8_t flags;
+
+ assert(alu(ALU_LSR, 2, 1, &flags) == 1);
+ assert(flags == 0);
+
+ assert(alu(ALU_LSR, 0x1, 1, &flags) == 0);
+ assert(flags & FLAG_ZERO);
+
+ assert(alu(ALU_LSR, 0x8000, 2, &flags) == 0x2000);
+ assert(flags == 0);
+}
+
+static void test_alu_noop(void) {
+ uint8_t flags;
+
+ assert(alu(ALU_NOOP, 7, 3, &flags) == 0);
+ assert(flags == 0);
+
+ assert(alu(ALU_NOOP, 4, 0, &flags) == 0);
+ assert(flags == 0);
+
+ assert(alu(ALU_NOOP, 18, 10002, &flags) == 0);
+ assert(flags == 0);
+}
+
+static void test_alu_rol(void) {
+ uint8_t flags;
+
+ assert(alu(ALU_ROL, 0x8000, 2, &flags) == 0x0002);
+ assert(flags == 0);
+
+ assert(alu(ALU_ROL, 0x4000, 1, &flags) == 0x8000);
+ assert(flags & FLAG_NEGATIVE);
+
+ assert(alu(ALU_ROL, 0x4000, 2, &flags) == 0x0001);
+ assert(flags == 0);
+
+ assert(alu(ALU_ROL, 0x4010, 1, &flags) == 0x8020);
+ assert(flags & FLAG_NEGATIVE);
+}
+
+static void test_alu_ror(void) {
+ uint8_t flags;
+
+ assert(alu(ALU_ROR, 0x8000, 2, &flags) == 0x2000);
+ assert(flags == 0);
+
+ assert(alu(ALU_ROR, 0x0001, 1, &flags) == 0x8000);
+ assert(flags & FLAG_NEGATIVE);
+
+ assert(alu(ALU_ROR, 0x4010, 1, &flags) == 0x2008);
+ assert(flags == 0);
+}
+
 int main(void) {
 
  puts("Running tests...");
 
  /* ALU TESTS */
  test_alu_add();
+ test_alu_sub();
  test_alu_and();
  test_alu_or();
  test_alu_not();
  test_alu_rb();
  test_alu_mul();
+ test_alu_div();
  test_alu_lsl();
+ test_alu_lsr();
+ test_alu_rol();
+ test_alu_ror();
+ test_alu_noop();
 
  return 0;
 }