From: notaz <notasas@gmail.com>
Date: Tue, 1 Nov 2022 23:20:50 +0000 (+0200)
Subject: cdrom: handle fifo overreads
X-Git-Tag: r24l~350
X-Git-Url: https://notaz.gp2x.de/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ca37f771036c862076cac9f7ca3145b15b8ecb9e;p=pcsx_rearmed.git

cdrom: handle fifo overreads

based on nocash doc
notaz/pcsx_rearmed#269
---

diff --git a/libpcsxcore/cdrom.c b/libpcsxcore/cdrom.c
index 12945d60..e1065739 100644
--- a/libpcsxcore/cdrom.c
+++ b/libpcsxcore/cdrom.c
@@ -1430,7 +1430,7 @@ void cdrWrite1(unsigned char rt) {
 }
 
 unsigned char cdrRead2(void) {
-	unsigned char ret = 0;
+	unsigned char ret = cdr.Transfer[0x920];
 
 	if (cdr.FifoOffset < cdr.FifoSize)
 		ret = cdr.Transfer[cdr.FifoOffset++];
@@ -1562,10 +1562,12 @@ void psxDma3(u32 madr, u32 bcr, u32 chcr) {
 			{
 				memcpy(ptr, cdr.Transfer + cdr.FifoOffset, size);
 				cdr.FifoOffset += size;
-				psxCpu->Clear(madr, size / 4);
 			}
-			if (size < cdsize)
+			if (size < cdsize) {
 				CDR_LOG_I("cdrom: dma3 %d/%d\n", size, cdsize);
+				memset(ptr + size, cdr.Transfer[0x920], cdsize - size);
+			}
+			psxCpu->Clear(madr, cdsize / 4);
 
 			CDRDMA_INT((cdsize/4) * 24);
 
@@ -1655,7 +1657,7 @@ int cdrFreeze(void *f, int Mode) {
 	if (Mode == 0) {
 		getCdInfo();
 
-		cdr.FifoOffset = tmp;
+		cdr.FifoOffset = tmp < DATA_SIZE ? tmp : DATA_SIZE;
 		cdr.FifoSize = (cdr.Mode & 0x20) ? 2340 : 2048 + 12;
 
 		// read right sub data