Adding Normmatt's BIOS as a built-in BIOS

Add options to select whether to boot from BIOS (default is no, as it is
now) and whether to use the original bios or the builtin one (default is
auto, which tries to use the official but falls back to the builtin if
not found).

1 files changed, 14 insertions, 4 deletions

diff --git a/cpu.c b/cpu.c
index 2c93f38..11c947f 100644
--- a/cpu.c
+++ b/cpu.c
@@ -4297,13 +4297,23 @@ void init_cpu(void)
   for(i = 0; i < 16; i++)
     reg[i] = 0;
 
-  reg[REG_SP] = 0x03007F00;
-  reg[REG_PC] = 0x08000000;
-  reg[REG_CPSR] = 0x0000001F;
   reg[CPU_HALT_STATE] = CPU_ACTIVE;
-  reg[CPU_MODE] = MODE_USER;
   reg[CHANGED_PC_STATUS] = 0;
 
+  if (selected_boot_mode == boot_game) {
+    reg[REG_SP] = 0x03007F00;
+    reg[REG_PC] = 0x08000000;
+    reg[REG_CPSR] = 0x0000001F;   // system mode
+    reg[CPU_MODE] = MODE_USER;
+  } else {
+    reg[REG_SP] = 0x03007F00;
+    reg[REG_PC] = 0x00000000;
+    reg[REG_CPSR] = 0x00000013 | 0xC0;  // supervisor
+    reg[CPU_MODE] = MODE_SUPERVISOR;
+  }
+
+  // Stack pointers are set by BIOS, we set them
+  // nevertheless, should we not boot from BIOS
   reg_mode[MODE_USER][5] = 0x03007F00;
   reg_mode[MODE_IRQ][5] = 0x03007FA0;
   reg_mode[MODE_FIQ][5] = 0x03007FA0;