feat: Clear Slot B on reset; Make Slot B savegames work

Author: Xeroxxx

src/memory.c

@@ -235,6 +235,7 @@ uint16_t sram_writeblock(void* buf, uint32_t addr, uint16_t size) {
 
 char current_filename[258];
 char slotb_filename[258];
+uint32_t slotb_ramsize_bytes = 0; /* Slot B SRAM size in bytes; 0 when no Slot B or no SRAM */
 uint32_t load_rom(uint8_t* filename, uint32_t base_addr, uint8_t flags) {
   UINT bytes_read;
   DWORD filesize;
@@ -389,6 +390,7 @@ uint32_t load_rom(uint8_t* filename, uint32_t base_addr, uint8_t flags) {
         /* Read Slot B SRAM size from ST header byte 0x37 (2KB units) */
         uint32_t slotb_ramsize = (uint32_t)sram_readbyte(0x600037) * 2048;
         slotb_rammask = slotb_ramsize ? (slotb_ramsize - 1) : 0;
+        slotb_ramsize_bytes = slotb_ramsize;
         /* Initialize Slot B SRAM region (0xE80000) and load from .srm file */
         if(slotb_ramsize) {
           sram_memset(0xE80000, slotb_ramsize, 0xFF);

src/memory.h

@@ -32,6 +32,7 @@
 
 extern char current_filename[];
 extern char slotb_filename[];
+extern uint32_t slotb_ramsize_bytes;
 
 #define MENU_ADDR_BRAM_SRC           (0xFF00)
 

src/snes.c

@@ -114,6 +114,11 @@ void prepare_reset() {
     save_srm(file_lfn, romprops.ramsize_bytes, SRAM_SAVE_ADDR);
     writeled(0);
   }
+  if(slotb_ramsize_bytes && fpga_test() == FPGA_TEST_TOKEN) {
+    writeled(1);
+    save_srm((uint8_t*)slotb_filename, slotb_ramsize_bytes, 0xE80000);
+    writeled(0);
+  }
   // don't save SGB RTC since we are in reset and it may be undefined
   rdyled(1);
   readled(1);
@@ -123,7 +128,8 @@ void prepare_reset() {
   snes_reset(1);
   fpga_dspx_reset(1);
   delay_ms(200);
-  slotb_filename[0] = 0; /* clear Slot B selection on every return-to-menu */
+  slotb_filename[0] = 0;     /* clear Slot B selection on every return-to-menu */
+  slotb_ramsize_bytes = 0;
 }
 
 void snes_init() {
@@ -314,6 +320,7 @@ uint8_t snes_main_loop() {
           printf("SaveRAM CRC: 0x%04lx; saving %s\n", saveram_crc, file_lfn);
           writeled(1);
           save_srm(file_lfn, romprops.ramsize_bytes, SRAM_SAVE_ADDR);
+          if(slotb_ramsize_bytes) save_srm((uint8_t*)slotb_filename, slotb_ramsize_bytes, 0xE80000);
           last_save_failed = save_failed;
           save_failed = file_res ? 1 : 0;
           didnotsave = save_failed ? 25 : 0;
@@ -324,6 +331,7 @@ uint8_t snes_main_loop() {
           diffcount=0;
           writeled(1);
           save_srm(file_lfn, romprops.ramsize_bytes, SRAM_SAVE_ADDR);
+          if(slotb_ramsize_bytes) save_srm((uint8_t*)slotb_filename, slotb_ramsize_bytes, 0xE80000);
           last_save_failed = save_failed;
           save_failed = file_res ? 1 : 0;
           didnotsave = save_failed ? 25 : 0;