Start of pulling up notes ...

src/mame/drivers/gunpey.c

@@ -1,5 +1,72 @@
 /********************************************************************************************
 
+	Gunpey (c) 2000 Banpresto
+
+ASM code study:
+0x84718 main code
+0x8472c call 0x81f34 reading of dip-switches
+0x84731 call 0x81f5c move dip-switches settings to work RAM
+0x84736 call 0x80ae4 writes to i/os 0x7fc0-0x7fff:
+	0x7fc0: 0x00
+	0x7fc1: 0x00
+	0x7fc2: 0x40
+	0x7fc3: 0x03
+	0x7fc4: 0x72
+	0x7fc5: 0x72
+	0x7fc6: 0x90
+	0x7fc7: 0x01
+	0x7fc8: 0x55 irq mask?
+	(note: skips irq ack)
+	0x7fca: 0x00
+	0x7fcb: 0x00
+	0x7fcc: 0x00
+	0x7fcd: 0x00
+	0x7fce: 0x00
+	0x7fcf: 0x07
+	0x7fd0: 0x00
+	0x7fd1: 0x00
+	0x7fd2: 0x00
+	0x7fd3: 0x8c
+	0x7fd4-0x7fde: 0x00
+	(skips 0x7fdf)
+	0x7fe0: 0x40
+	0x7fe1: 0x02
+	0x7fe2: 0x00
+	0x7fe3: 0x00
+	0x7fe4: 0x60
+	0x7fe5: 0x07
+	0x7fe6: 0x88
+	0x7fe7: 0x07
+	0x7fe8: 0x9f
+	0x7fe9: 0x08
+	0x7fea: 0x77
+	0x7feb: 0x08
+	(here the code writes 16-bit words, read from 0x500e ...)
+	0x7fec: 0x00
+	0x7fed: 0x84
+	(read from 0x5012)
+	0x7fee: 0x00
+	0x7fef: 0x88
+	(returns to byte filling)
+	0x7ff0: 0x84
+	0x7ff1: 0x00
+	0x7ff2: 0x00
+	0x7ff3: 0x01
+	0x7ff4: 0x00
+	0x7ff5: 0x00
+	0x7ff6: 0xc7
+	0x7ff7: 0x56
+	0x7ff8: 0x3f
+	0x7ff9: 0x48
+	0x7ffa: 0x9a
+	0x7ffb: 0x22
+	0x7ffc: 0x0e
+	0x7ffd: 0x43
+	0x7ffe: 0xf0
+	0x7fff: 0x15
+Then, it fills the following work RAMs (with 0 except where noted):
+0x5e36, 0x5e38, 0x5e44, 0x5e46 (4), 0x5e48, 0x5e4a, 0x5e40, 0x5e42, 0x5b68 (0x9c8), 0x5b6a (0x9c8), 0x59c4 (1)
+0x8473b: call 0x81415 (TODO)
 
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