Decode SGB system control packets

1 files changed, 105 insertions, 37 deletions

diff --git a/data/sgb/ctrl_packets.inc b/data/sgb/ctrl_packets.inc
index bcca0ed..b613e7d 100644
--- a/data/sgb/ctrl_packets.inc
+++ b/data/sgb/ctrl_packets.inc
@@ -1,60 +1,128 @@
-PalTrnPacket:
-	db $59, $00, $00, $00, $00, $00, $00, $00
-	db $00, $00, $00, $00, $00, $00, $00, $00
+sgb_pal_trn: MACRO
+	db (SGB_PAL_TRN << 3) + 1
+	ds 15
+ENDM
 
-MltReq1Packet:
-	db $89, $00, $00, $00, $00, $00, $00, $00
-	db $00, $00, $00, $00, $00, $00, $00, $00
+sgb_mlt_req: MACRO
+	db (SGB_MLT_REG << 3) + 1
+	db \1 - 1
+	ds 14
+ENDM
 
-MltReq2Packet:
-	db $89, $01, $00, $00, $00, $00, $00, $00
-	db $00, $00, $00, $00, $00, $00, $00, $00
+sgb_chr_trn: MACRO
+	db (SGB_CHR_TRN << 3) + 1
+	db \1 + (\2 << 1)
+	ds 14
+ENDM
 
-ChrTrnPacket:
-	db $99, $00, $00, $00, $00, $00, $00, $00
-	db $00, $00, $00, $00, $00, $00, $00, $00
+sgb_pct_trn: MACRO
+	db (SGB_PCT_TRN << 3) + 1
+	ds 15
+ENDM
 
-PctTrnPacket:
-	db $a1, $00, $00, $00, $00, $00, $00, $00
-	db $00, $00, $00, $00, $00, $00, $00, $00
+sgb_mask_en: MACRO
+	db (SGB_MASK_EN << 3) + 1
+	db \1
+	ds 14
+ENDM
 
-MaskEnFreezePacket:
-	db $b9, $01, $00, $00, $00, $00, $00, $00
-	db $00, $00, $00, $00, $00, $00, $00, $00
+sgb_data_snd: MACRO
+	db (SGB_DATA_SND << 3) + 1
+	dw \1 ; address
+	db \2 ; bank
+	db \3 ; length (1-11)
+ENDM
 
-MaskEnCancelPacket:
-	db $b9, $00, $00, $00, $00, $00, $00, $00
-	db $00, $00, $00, $00, $00, $00, $00, $00
+PalTrnPacket: sgb_pal_trn
+MltReq1Packet: sgb_mlt_req 1
+MltReq2Packet: sgb_mlt_req 2
+ChrTrnPacket: sgb_chr_trn 0, 0
+PctTrnPacket: sgb_pct_trn
+
+MaskEnFreezePacket: sgb_mask_en 1
+MaskEnCancelPacket: sgb_mask_en 0
+
+; These are packets containing SNES code.
+; This set of packets is found in several Japanese SGB-compatible titles.
+; It appears to be part of NCL's SGB devkit.
 
 DataSndPacket1:
-	db $79, $5d, $08, $00, $0b, $8c, $d0, $f4
-	db $60, $00, $00, $00, $00, $00, $00, $00
+	sgb_data_snd $085d, $0, 11
+	db  $8c                 ; cpx #$8c (2)
+	db  $d0, $f4            ; bne -$0c
+	db  $60                 ; rts
+	ds  7
 
 DataSndPacket2:
-	db $79, $52, $08, $00, $0b, $a9, $e7, $9f
-	db $01, $c0, $7e, $e8, $e8, $e8, $e8, $e0
+	sgb_data_snd $0852, $0, 11
+	db  $a9, $e7            ; lda #$e7
+	db  $9f, $01, $c0, $7e  ; sta $7ec001, x
+	db  $e8                 ; inx
+	db  $e8                 ; inx
+	db  $e8                 ; inx
+	db  $e8                 ; inx
+	db  $e0                 ; cpx #$8c (1)
 
 DataSndPacket3:
-	db $79, $47, $08, $00, $0b, $c4, $d0, $16
-	db $a5, $cb, $c9, $05, $d0, $10, $a2, $28
+	sgb_data_snd $0847, $0, 11
+	db  $c4                 ; cmp #$c4 (2)
+	db  $d0, $16            ; bne +$16
+	db  $a5                 ; lda dp
+	db  $cb                 ; wai
+	db  $c9, $05            ; cmp #$05
+	db  $d0, $10            ; bne +$10
+	db  $a2, $28            ; ldx #$28
 
 DataSndPacket4:
-	db $79, $3c, $08, $00, $0b, $f0, $12, $a5
-	db $c9, $c9, $c8, $d0, $1c, $a5, $ca, $c9
+	sgb_data_snd $083c, $0, 11
+	db  $f0, $12            ; beq +$12
+	db  $a5                 ; lda dp
+	db  $c9, $c9            ; cmp #$c9
+	db  $c8                 ; iny
+	db  $d0, $1c            ; bne +$1c
+	db  $a5                 ; lda dp
+	db  $ca                 ; dex
+	db  $c9                 ; cmp #$c4 (1)
 
 DataSndPacket5:
-	db $79, $31, $08, $00, $0b, $0c, $a5, $ca
-	db $c9, $7e, $d0, $06, $a5, $cb, $c9, $7e
+	sgb_data_snd $0831, $0, 11
+	dbw $0c, $caa5          ; tsb $caa5
+	db  $c9, $7e            ; cmp #$7e
+	db  $d0, $06            ; bne +$06
+	db  $a5                 ; lda dp
+	db  $cb                 ; wai
+	db  $c9, $7e            ; cmp #$7e
 
 DataSndPacket6:
-	db $79, $26, $08, $00, $0b, $39, $cd, $48
-	db $0c, $d0, $34, $a5, $c9, $c9, $80, $d0
+	sgb_data_snd $0826, $0, 11
+	db  $39                 ; bne +$39 (2)
+	dbw $cd, $0c48          ; cmp $0c48
+	db  $d0, $34            ; bne +$34
+	db  $a5                 ; lda dp
+	db  $c9, $c9            ; cmp #$c9
+	db  $80, $d0            ; bra -$30
 
 DataSndPacket7:
-	db $79, $1b, $08, $00, $0b, $ea, $ea, $ea
-	db $ea, $ea, $a9, $01, $cd, $4f, $0c, $d0
+	sgb_data_snd $081b, $0, 11
+	db  $ea                 ; nop
+	db  $ea                 ; nop
+	db  $ea                 ; nop
+	db  $ea                 ; nop
+	db  $ea                 ; nop
+	                        ; $0820:
+	db  $a9, $01            ; lda #01
+	dbw $cd, $0c4f          ; cmp $c4f
+	db  $d0                 ; bne +$39 (1)
 
 DataSndPacket8:
-	db $79, $10, $08, $00, $0b, $4c, $20, $08
-	db $ea, $ea, $ea, $ea, $ea, $60, $ea, $ea
+	sgb_data_snd $0810, $0, 11
+	dbw $4c, $0820          ; jmp $0820
+	db  $ea                 ; nop
+	db  $ea                 ; nop
+	db  $ea                 ; nop
+	db  $ea                 ; nop
+	db  $ea                 ; nop
+	db  $60                 ; rts
+	db  $ea                 ; nop
+	db  $ea                 ; nop