From a1e12fc59450a8168ce78d500eec3294d090d1b4 Mon Sep 17 00:00:00 2001
From: Max Regan <mgregan2@gmail.com>
Date: Sat, 8 Sep 2018 21:35:22 -0700
Subject: [PATCH] cpu: make blarg cpu instr test 7 pass

---
 src/gbemu/cpu.c | 20 +++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/src/gbemu/cpu.c b/src/gbemu/cpu.c
index 89c1d22..f70f274 100644
--- a/src/gbemu/cpu.c
+++ b/src/gbemu/cpu.c
@@ -615,7 +615,7 @@ int lr35902_cycle(struct lr35902_state *cpu)
 		break;
 	case 0x35: /* DEC (HL) */
 		val = gb_mem_read(cpu->memory, cpu->hl);
-		cpu->hf = CALC_H_ADD(val, 1);
+		cpu->hf = CALC_H_SUB(val, 1);
 		cpu->zf = (val == 0);
 		cpu->nf = 1;
 		val--;
@@ -1586,7 +1586,7 @@ int lr35902_cycle(struct lr35902_state *cpu)
 		}
 		break;
 	case 0xd4: /* CALL NC */
-		if (!cpu->nf) {
+		if (!cpu->cf) {
 			CALL(cpu);
 		} else {
 			cpu->pc += 2;
@@ -1608,13 +1608,16 @@ int lr35902_cycle(struct lr35902_state *cpu)
 		}
 		break;
 	case 0xd9: /* RETI */
-		gb_log("Interrupts ON\n");
 		RET(cpu);
-		ASSERT(0);
 		cpu->int_state = LR35902_INT_ON;
 		break;
-	case 0xda:
-		ASSERT(0);
+	case 0xda: /* JP C, a16 */
+		val_16 = gb_mem_read(cpu->memory, cpu->pc++);
+		val_16 |= ((uint16_t) gb_mem_read(cpu->memory, cpu->pc++) << 8);
+		if (cpu->cf) {
+			cpu->pc = val_16;
+		}
+		break;
 	case 0xdb: /* UNDEF */
 		break;
 	case 0xdc: /* CALL C */
@@ -1627,7 +1630,7 @@ int lr35902_cycle(struct lr35902_state *cpu)
 	case 0xdd: /* UNDEF */
 		ASSERT(0);
 		break;
-	case 0xde:
+	case 0xde: /* SBC A, d8 */
 		ASSERT(0);
 	case 0xdf: /* RST 0x18 */
 		RST(cpu, 0x18);
@@ -1704,7 +1707,6 @@ int lr35902_cycle(struct lr35902_state *cpu)
 		cpu->a = gb_mem_read(cpu->memory, 0xFF00 + cpu->c);
 		break;
 	case 0xf3: /* DI */
-		gb_log("Interrupts OFF\n");
 		/*TODO: implement me */
 	case 0xf4: /* UNDEF */
 		break;
@@ -1743,7 +1745,7 @@ int lr35902_cycle(struct lr35902_state *cpu)
 		cpu->a = gb_mem_read(cpu->memory, val_16);
 		break;
 	case 0xfb: /* EI */
-		gb_log("Interrupts ON\n");
+		/* TODO: implement me */
 		break;
 	case 0xfc: /* UNDEF */
 		ASSERT(0);