libretro: empty srm prevention hack

diff --git a/platform/libretro.c b/platform/libretro.c
index ee15d9c..23f0694 100644 (file)
--- a/platform/libretro.c
+++ b/platform/libretro.c
@@ -741,14 +741,25 @@ void *retro_get_memory_data(unsigned id)
 
 size_t retro_get_memory_size(unsigned id)
 {
+       unsigned int i;
+       int sum;
+
        if (id != RETRO_MEMORY_SAVE_RAM)
                return 0;
 
        if (PicoAHW & PAHW_MCD)
                // bram
                return 0x2000;
-       else
+
+       if (Pico.m.frame_count == 0)
                return SRam.size;
+
+       // if game doesn't write to sram, don't report it to
+       // libretro so that RA doesn't write out zeroed .srm
+       for (i = 0, sum = 0; i < SRam.size; i++)
+               sum |= SRam.data[i];
+
+       return (sum != 0) ? SRam.size : 0;
 }
 
 void retro_reset(void)