psxmem: Reads of PIO Expansion area read all-ones.

Patch by senquack :
"Fixes 'Tetris with Card Captor Sakura - Eternal Heart (Japan)' startup.
Thanks to gameblabla for finding this issue and pointing out that
Mednafen had a fix for it. It's adapted here in a much simpler form."

diff --git a/libpcsxcore/psxmem.c b/libpcsxcore/psxmem.c
index 14fd911..a1a641d 100644 (file)
--- a/libpcsxcore/psxmem.c
+++ b/libpcsxcore/psxmem.c
@@ -187,7 +187,7 @@ void psxMemReset() {
        char bios[1024];
 
        memset(psxM, 0, 0x00200000);
-       memset(psxP, 0, 0x00010000);
+       memset(psxP, 0xff, 0x00010000);
 
        if (strcmp(Config.Bios, "HLE") != 0) {
                sprintf(bios, "%s/%s", Config.BiosDir, Config.Bios);