updated to last SGDK

iratahack · Jul 12, 2023 · e3bcd94 · e3bcd94
1 parent ba2a3ff
commit e3bcd94
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Showing 3 changed files with 20 additions and 29 deletions.
diff --git a/sample/platformer/out/rom.bin b/sample/platformer/out/rom.bin
diff --git a/sample/platformer/src/boot/rom_head.c b/sample/platformer/src/boot/rom_head.c
@@ -9,7 +9,7 @@ const ROMHeader rom_header = {
 #else
     "SEGA MEGA DRIVE ",
 #endif
-    "(C)SGDK 2022    ",
+    "(C)SGDK 2023    ",
     "SAMPLE PROGRAM                                  ",
     "SAMPLE PROGRAM                                  ",
     "GM 00000000-00",

diff --git a/sample/platformer/src/boot/sega.s b/sample/platformer/src/boot/sega.s
@@ -52,49 +52,40 @@ rom_header:
         .incbin "out/rom_head.bin", 0, 0x100
 
 _Entry_Point:
+* disable interrupts
         move    #0x2700,%sr
+
+* Configure a USER_STACK_LENGTH bytes user stack at bottom, and system stack on top of it
+        move    %sp, %usp
+        sub     #USER_STACK_LENGTH, %sp
+
+* Halt Z80 (need to be done as soon as possible on reset)
+        move.l  #0xA11100,%a0       /* Z80_HALT_PORT */
+        move.w  #0x0100,%d0
+        move.w  %d0,(%a0)           /* HALT Z80 */
+        move.w  %d0,0x0100(%a0)     /* END RESET Z80 */
+
         tst.l   0xa10008
-        bne.s   SkipJoyDetect
+        bne.s   SkipInit
 
         tst.w   0xa1000c
+        bne.s   SkipInit
 
-SkipJoyDetect:
-        bne.s   SkipSetup
-
-        lea     Table,%a5
-        movem.w (%a5)+,%d5-%d7
-        movem.l (%a5)+,%a0-%a4
 * Check Version Number
-        move.b  -0x10ff(%a1),%d0
+        move.b  -0x10ff(%a0),%d0
         andi.b  #0x0f,%d0
-        beq.s   WrongVersion
+        beq.s   NoTMSS
 
 * Sega Security Code (SEGA)
-        move.l  #0x53454741,0x2f00(%a1)
-WrongVersion:
-* Read from the control port to cancel any pending read/write command
-        move.w  (%a4),%d0
-
-* Configure a USER_STACK_LENGTH bytes user stack at bottom, and system stack on top of it
-        move    %sp, %usp
-        sub     #USER_STACK_LENGTH, %sp
-
-        move.w  %d7,(%a1)
-        move.w  %d7,(%a2)
-
-* Jump to initialisation process now...
+        move.l  #0x53454741,0x2f00(%a0)
 
+NoTMSS:
         jmp     _start_entry
 
-SkipSetup:
+SkipInit:
         jmp     _reset_entry
 
 
-Table:
-        dc.w    0x8000,0x3fff,0x0100
-        dc.l    0xA00000,0xA11100,0xA11200,0xC00000,0xC00004
-
-
 *------------------------------------------------
 *
 *       interrupt functions