From 25d1e99571271d8277069e58c106e4d959b9617f Mon Sep 17 00:00:00 2001
From: Mahyar Koshkouei <mk@deltabeard.com>
Date: Wed, 23 Mar 2022 23:40:51 +0000
Subject: [PATCH] peanut-gb: detect when ROM has halted forever

Signed-off-by: Mahyar Koshkouei <mk@deltabeard.com>
---
 inc/peanut_gb.h |  8 ++++++++
 src/main.c      | 17 +++++++++++++++--
 2 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/inc/peanut_gb.h b/inc/peanut_gb.h
index d6f5b85..de43b18 100644
--- a/inc/peanut_gb.h
+++ b/inc/peanut_gb.h
@@ -490,6 +490,8 @@ struct gb_s
 			uint8_t joypad;
 		};
 
+		unsigned ended : 1;
+
 		/* Implementation defined data. Set to NULL if not required. */
 		void *priv;
 	} direct;
@@ -2200,6 +2202,11 @@ void __gb_step_cpu(struct gb_s *gb)
 	case 0x76: /* HALT */
 		/* TODO: Emulate HALT bug? */
 		gb->gb_halt = 1;
+		if(gb->gb_reg.IE == 0)
+		{
+			gb->direct.ended = 1;
+			return;
+		}
 		break;
 
 	case 0x77: /* LD (HL), A */
@@ -3636,6 +3643,7 @@ void gb_reset(struct gb_s *gb)
 	gb->gb_reg.IE        = 0x00;
 
 	gb->direct.joypad = 0xFF;
+	gb->direct.ended = 0;
 	gb->gb_reg.P1 = 0xCF;
 
 	memset(gb->vram, 0x00, VRAM_SIZE);
diff --git a/src/main.c b/src/main.c
index 86c8fe4..a076360 100644
--- a/src/main.c
+++ b/src/main.c
@@ -128,11 +128,24 @@ int main(void)
 
 	gb_init_serial(&gb, gb_serial_tx, gb_serial_rx);
 
-	while(1)
-		gb_run_frame(&gb);
+	uint_fast32_t instrs = 0;
+	uint64_t start_time = time_us_64();
+	uint64_t end_time;
+	while(!gb.direct.ended)
+	{
+		__gb_step_cpu(&gb);
+		instrs++;
+	}
+
+	end_time = time_us_64();
+
+	puts("\nEmulation Ended");
+	printf("Instructions: %u\n"
+	       "Time: %llu us\n", instrs, end_time-start_time);
 
 	/* Sleep forever. */
 sleep:
+	stdio_flush();
 	while(1)
 		__wfi();