psxbios: Add checks for strcpy & strncpy.

This should be closer to documentation.

diff --git a/libpcsxcore/psxbios.c b/libpcsxcore/psxbios.c
index be3abb8..13cfe73 100644 (file)
--- a/libpcsxcore/psxbios.c
+++ b/libpcsxcore/psxbios.c
@@ -630,6 +630,12 @@ void psxBios_strncmp() { // 0x18
 
 void psxBios_strcpy() { // 0x19
        char *p1 = (char *)Ra0, *p2 = (char *)Ra1;
+       if (a0 == 0 || a1 == 0)
+       {
+               v0 = 0;
+               pc0 = ra;
+               return;
+       }
        while ((*p1++ = *p2++) != '\0');
 
        v0 = a0; pc0 = ra;
@@ -638,7 +644,12 @@ void psxBios_strcpy() { // 0x19
 void psxBios_strncpy() { // 0x1a
        char *p1 = (char *)Ra0, *p2 = (char *)Ra1;
        s32 n = a2, i;
-
+       if (a0 == 0 || a1 == 0)
+       {
+               v0 = 0;
+               pc0 = ra;
+               return;
+       }
        for (i = 0; i < n; i++) {
                if ((*p1++ = *p2++) == '\0') {
                        while (++i < n) {