Cartridge boot code?

[swapd0]

This is my cartridge boot code, it just copy the code to address 0x4000 and jumps there, but it doesn't work with TombRaider. But if I upload the out.jag file to the  Jaguar RAM at 0x4000 and have "this" ROM burned into the skunk board it works (I need it to load the assets).

 

What on the hell I'm doing wrong?, there are any difference (jaguar status) when I press up to launch the ROM and when I upload something using jcp?

 

This is driving me crazy. ?

 

	.include "jaguar/jaguar.inc"

	.org ROM + $2000

boot_code:
	move.w #$2700,sr			; disable all interrups
	move.w #0xffff,VI

	lea code_start,a0
	lea $4000.w,a1
	move.l #code_end,d7
	sub.l a0,d7
	asr.l #2,d7
.loop:
	move.l (a0)+,(a1)+
	dbf d7,.loop

	jmp $4000.w

	.long
assets:
	.incbin "assets.fs"

	.long
code_start:
	.incbin "out.jag"
	.long
code_end:

 

[42bs]

Is out.jag a pure binary? JCP will strip a header.

I will check my JagTris code, where  I do the same.

Edited February 6, 2022 by 42bs

[swapd0]

out.jag has no header, also I'm using this in BurgerTom and it works.

 

[42bs]

What about the size? Is it <= 256k? Did you try subq.l/bne instead dbra?

[swapd0]

out.jag is 291,574 bytes. By the way, it hangs before C main() function is called.

Edited February 6, 2022 by swapd0

[42bs]

You cannot copy with dbra then. Dbra uses the lower 16bits of the register. You need a sub.l #0x10000,D7 after the dbra.

[42bs]

Or copy 8 byte wise.

[swapd0]

1 hour ago, 42bs said:

You cannot copy with dbra then. Dbra uses the lower 16bits of the register. You need a sub.l #0x10000,D7 after the dbra.

Lol, what a stupid mistake!, it was a long time ago since I don't code for the 68000, only small routines, I bet that with a debugger I could find it very quickly.

[42bs]

6 hours ago, swapd0 said:

Lol, what a stupid mistake!, it was a long time ago since I don't code for the 68000, only small routines, I bet that with a debugger I could find it very quickly.

I know this. I mainly program ARM (work) and 65C02 (fun). When I switch to 68K or GPU/DSP I need to check back with the manual for certain opcodes.