nuclear@4: | vi:filetype=gas68k:
nuclear@0: 	.text
nuclear@0: 	.extern main
nuclear@0: 
nuclear@0: 	.global start
nuclear@0: 	.global halt_cpu
nuclear@0: start:
nuclear@1: 	jsr disable_intr
nuclear@0: 
nuclear@12: 	| write SEGA to 0xa14000 to convience the TMSS to run us
nuclear@12: 	move.l 0x100, %d0
nuclear@12: 	move.l %d0, 0xa14000
nuclear@12: 
nuclear@0: 	| copy .data section from ROM to RAM
nuclear@0: 	move.l #_data_lma, %a0
nuclear@0: 	move.l #_data_start, %a1
nuclear@0: 	move.l #_data_end, %a2
nuclear@0: 	cmp.l %a1, %a2
nuclear@0: 	beq.s 1f	| skip data copy if the section is empty
nuclear@0: 0:	move.l (%a0)+, (%a1)+
nuclear@0: 	cmp.l %a1, %a2
nuclear@0: 	bne.s 0b
nuclear@0: 1:
nuclear@0: 
nuclear@0: 	| zero the .bss section
nuclear@0: 	move.l #_bss_start, %a0
nuclear@0: 	move.l #_bss_end, %a1
nuclear@0: 	cmp.l %a0, %a1
nuclear@0: 	beq.s 1f	| skip bss zeroing if the section is empty
nuclear@0: 0:	clr.l (%a0)+
nuclear@0: 	cmp.l %a0, %a1
nuclear@0: 	bne.s 0b
nuclear@0: 1:
nuclear@0: 
nuclear@0: 	| setup the stack pointer stack
nuclear@0: 	move.l #_stacktop, %sp
nuclear@0: 	| now that we have a stack, we can enable interrupts
nuclear@1: 	jsr enable_intr
nuclear@0: 
nuclear@0: 	jsr main
nuclear@0: halt_cpu:
nuclear@0: 	stop #0x2700