hexed: add simple io commands

[megadrive.git] / hexed / transfer.S

diff --git a/hexed/transfer.S b/hexed/transfer.S
index 4ab3aff..0115dd9 100644 (file)
--- a/hexed/transfer.S
+++ b/hexed/transfer.S
@@ -108,6 +108,10 @@ recv_ad:
        move.l          d2,d0
        rts
 
+send_byte:
+       send_one_byte
+       rts
+
 
 do_transfer:
        lea             0xa10005,a1
@@ -132,9 +136,11 @@ jumptab:
        bra             pcc_transfer_recv       /* sent to us */
        bra             pcc_transfer_send       /* recv from us */
        bra             pcc_jump
+       bra             pcc_io
        bra             pcc_test_code
 
 
+/* receive data from PC */
 pcc_transfer_recv:
        bsr             recv_ad
        move.l          d0,a0
@@ -149,13 +155,14 @@ tr_recv_loop:
        bra             return
 
 
+/* send data to PC */
 pcc_transfer_send:
        bsr             recv_ad
        move.l          d0,a0
        bsr             recv_ad
        move.l          d0,d3
 
-0: /*Lwait_tl_low:*/
+0: /*Lwait_tl_low: it should switch to rx mode before lowering tl */
        move.b          (a1),d0
        btst.b          #4,d0
        bne             0b /*Lwait_tl_low*/
@@ -171,16 +178,124 @@ tr_send_loop:
        bra             return
 
 
+/* call specified location */
 pcc_jump:
        bsr             recv_ad
        move.l          d0,a0
-       jmp             (a0)
+       jsr             (a0)
+       bra             return
+
+
+/* do simple i/o commands */
+pcc_io:
+       moveq.l         #0,d4
+       bsr             recv_byte
+       move.b          d0,d4
+       bsr             recv_byte
+       lsl.l           #8,d4
+       move.b          d0,d4
 
+pcc_io_loop:
+       move.b          #0x40,(0xa1000b).l      /* input mode */
 
+       sub.w           #1,d4
+       bmi             return
+
+       bsr             recv_byte
+       move.b          d0,d3                   /* cmd */
+
+       bsr             recv_ad
+       move.l          d0,a2                   /* addr */
+
+       cmp.b           #IOSEQ_W32, d3
+       beq             pcc_io_w32
+       cmp.b           #IOSEQ_W16, d3
+       beq             pcc_io_w16
+       cmp.b           #IOSEQ_W8, d3
+       bne             pcc_io_rx
+
+pcc_io_w8:
+       bsr             recv_byte
+       move.b          d0,(a2)
+       bra             pcc_io_loop
+
+pcc_io_w16:
+       bsr             recv_byte
+       move.b          d0,d3
+       bsr             recv_byte
+       lsl.w           #8,d3
+       move.b          d0,d3
+       move.w          d3,(a2)
+       bra             pcc_io_loop
+
+pcc_io_w32:
+       bsr             recv_byte
+       move.b          d0,d3
+       bsr             recv_byte
+       lsl.w           #8,d3
+       move.b          d0,d3
+       bsr             recv_byte
+       lsl.l           #8,d3
+       move.b          d0,d3
+       bsr             recv_byte
+       lsl.l           #8,d3
+       move.b          d0,d3
+       move.l          d3,(a2)
+       bra             pcc_io_loop
+
+pcc_io_rx:
+0: /*Lwait_tl_low:*/
+       move.b          (a1),d0
+       btst.b          #4,d0
+       bne             0b /*Lwait_tl_low*/
+
+       move.b          #0x4f,(0xa1000b).l
+       move.b          #0x40,(a1)
+
+       cmp.b           #IOSEQ_R32, d3
+       beq             pcc_io_r32
+       cmp.b           #IOSEQ_R16, d3
+       beq             pcc_io_r16
+       cmp.b           #IOSEQ_R8, d3
+       bne             return
+
+pcc_io_r8:
+       move.b          (a2),d0
+       bsr             send_byte
+       bra             pcc_io_loop
+
+pcc_io_r16:
+       move.w          (a2),d3
+       move.w          d3,d0
+       lsr.w           #8,d0
+       bsr             send_byte
+       move.b          d3,d0
+       bsr             send_byte
+       bra             pcc_io_loop
+
+pcc_io_r32:
+       move.l          (a2),d3
+       move.l          d3,d0
+       swap            d0
+       lsr.l           #8,d0
+       bsr             send_byte
+       move.l          d3,d0
+       swap            d0
+       bsr             send_byte
+       move.w          d3,d0
+       lsr.w           #8,d0
+       bsr             send_byte
+       move.b          d3,d0
+       bsr             send_byte
+       bra             pcc_io_loop
+
+
+/* some random code */
 pcc_test_code:
        bra             return
 
 
+
 return:
        move.b          #0,(0xa1000b).l /* all inputs */
        move.l          #0xffe000,a1