megaed-sv: tas sync code

[megadrive.git] / megaed-sv / asmtools.s

diff --git a/megaed-sv/asmtools.s b/megaed-sv/asmtools.s
index db93940..5e3ae7a 100644 (file)
--- a/megaed-sv/asmtools.s
+++ b/megaed-sv/asmtools.s
@@ -6,7 +6,7 @@
 .endm
 
 
-.globl read_joy_responses /* u8 *rbuf */
+.global read_joy_responses /* u8 *rbuf */
 read_joy_responses:
     ldarg       0, 0, a1
     movem.l     d2-d7, -(sp)
@@ -49,4 +49,118 @@ read_joy_responses:
     rts
 
 
+.global run_game /* u16 mapper, int tas_sync */
+run_game:
+       move.w          #0x2700, sr
+    ldarg       0, 0, d7
+    ldarg       1, 0, d6
+    move.l      #0xa10000, a6
+    move.l      #0xc00000, a5
+    move.l      #0xc00005, a4
+    move.l      #0xc00004, a3
+    moveq.l     #0x00, d2
+    move.b      #0xff, d3
+    move.b      #0x40, d4
+    move.b      d4, (0x09,a6) /* CtrlA */
+    move.b      d2, (0x0b,a6) /* CtrlB */
+    move.b      d2, (0x0d,a6) /* CtrlC */
+    move.b      d2, (0x13,a6) /* S-CtrlA */
+    move.b      d3, (0x0f,a6) /* TxDataA */
+    move.b      d2, (0x19,a6) /* S-CtrlB */
+    move.b      d3, (0x15,a6) /* TxDataB */
+    move.b      d2, (0x1f,a6) /* S-CtrlC */
+    move.b      d3, (0x1b,a6) /* TxDataC */
+
+    /* set up for vram write */
+    move.l      #0x40000000, (a3)
+
+    move.l      #0xff0000, a1
+    move.l      #0x10000/4/4-1, d0
+0:
+    move.l      d2, (a1)+
+    move.l      d2, (a1)+
+    move.l      d2, (a1)+
+    move.l      d2, (a1)+
+    dbra        d0, 0b
+
+    move.l      #0xfffe00, a1
+    tst.l       d6
+    bne         use_tas_code
+
+    lea         (run_game_r,pc), a0
+    move.l      #(run_game_r_end - run_game_r)/2-1, d0
+    bra         0f
+use_tas_code:
+    lea         (run_game_r_tas,pc), a0
+    move.l      #(run_game_r_tas_end - run_game_r_tas)/2-1, d0
+
+0:
+    move.w      (a0)+, (a1)+
+    dbra        d0, 0b
+    jmp         0xfffe00
+
+run_game_r:
+    move.w      #0x3210, (0xA13006)
+
+    move.w      d7, (0xA13010)
+    move.w      #0, (0xA13000)
+    
+    move.l      (0x00), a7
+    move.l      (0x04), a0
+    jmp         (a0)
+run_game_r_end:
+
+run_game_r_tas:
+    move.w      #0x3210, (0xA13006)
+    move.w      d7, (0xA13010)
+    move.w      #0, (0xA13000)
+    
+    move.l      (0x00), a7
+    move.l      (0x04), a0
+
+0:  /* wait for special code */
+    move.b      d4, (0x03,a6)
+    move.b      (0x03,a6), d0
+    move.b      d2, (0x03,a6)
+    move.b      (0x03,a6), d1
+    and.b       #0x3f, d0
+    cmp.b       d0, d1
+    bne         0b
+    cmp.b       #0x25, d0
+    bne         0b
+
+0:  /* wait for special code to end */
+    cmp.b       (0x03,a6), d0
+    beq         0b
+
+    /* wait for active display */
+    moveq.l     #3, d0
+0:
+    btst        d0, (a4)      /* 8 */
+    beq.s       0b            /* 10 */
+0:
+    btst        d0, (a4)
+    bne.s       0b
+
+    /* flood the VDP FIFO */
+.rept 5
+    move.w      d2, (a5)
+.endr
+
+    /* doesn't help.. */
+.if 0
+.rept 94
+    nop
+.endr
+    move.l      #0x93049400, (a3) /* DMALEN LO/HI = 0x0008 */
+    move.l      #0x95009601, (a3) /* DMA SRC LO/MID */
+    move.l      #0x977f8114, (a3) /* DMA SRC HI/MODE, Turn off Display */
+    move.l      #0xc0000080, (a3) /* start DMA */
+.endif
+
+    move.b      d2, (0x09,a6) /* CtrlA */
+    move.b      d4, (0x03,a6)
+    jmp         (a0)
+run_game_r_tas_end:
+
 # vim:filetype=asmM68k:ts=4:sw=4:expandtab