psxbios: Add checks for bcopy

Nocash documentation say that function refuses to copy any data
if dst is NULL or len greater than 0x7FFFFFFF.
(In any cases, return value is always dst)

diff --git a/libpcsxcore/psxbios.c b/libpcsxcore/psxbios.c
index 67a01e5..4019234 100644 (file)
--- a/libpcsxcore/psxbios.c
+++ b/libpcsxcore/psxbios.c
@@ -739,15 +739,20 @@ void psxBios_tolower() { // 0x26
 
 void psxBios_bcopy() { // 0x27
        char *p1 = (char *)Ra1, *p2 = (char *)Ra0;
+       v0 = a0;
+       if (a0 == 0 || a2 > 0x7FFFFFFF)
+       {
+               pc0 = ra;
+               return;
+       }
        while ((s32)a2-- > 0) *p1++ = *p2++;
-
+       a2 = 0;
        pc0 = ra;
 }
 
 void psxBios_bzero() { // 0x28
        char *p = (char *)Ra0;
        while ((s32)a1-- > 0) *p++ = '\0';
-
        pc0 = ra;
 }