Reading from Z80 bus when Z80 is not bus requested should return open bus. Fixes regression in Metal Sonic Rebooted

1 files changed, 2 insertions, 1 deletions

diff --git a/genesis.c b/genesis.c
index 6b6ba13..c6dc8c0 100644
--- a/genesis.c
+++ b/genesis.c
@@ -888,7 +888,8 @@ static uint8_t io_read(uint32_t location, m68k_context * context)
 				value = 0xFF;
 			}
 		} else {
-			value = 0xFF;
+			uint16_t word = get_open_bus_value(&gen->header);
+			value = location & 1 ? word : word >> 8;
 		}
 	} else {
 		if (location < 0x10100) {