psxbios : Add checks to memset.

This now can be a tricky pony and an improper memset implementation means that
you can't play Tomb Raider 4 properly.
(Trying to put in the eye of horus will just result in Lara sidestepping)

This should hopefully be fixed (and follows nocash doc).

diff --git a/libpcsxcore/psxbios.c b/libpcsxcore/psxbios.c
index b327632..97c7951 100644 (file)
--- a/libpcsxcore/psxbios.c
+++ b/libpcsxcore/psxbios.c
@@ -805,8 +805,19 @@ void psxBios_memcpy() { // 0x2a
 
 void psxBios_memset() { // 0x2b
        char *p = (char *)Ra0;
+       v0 = a0;
+       if (a2 > 0x7FFFFFFF || a2 == 0)
+       {
+               v0 = 0;
+               pc0 = ra;
+               return;
+       }
+       if (a0 == 0)
+       {
+               pc0 = ra;
+               return;
+       }
        while ((s32)a2-- > 0) *p++ = (char)a1;
-
        a2 = 0;
        v0 = a0; pc0 = ra;
 }