task_switch.S

	.h8300sx
	.section .text

	.global _switch_without_restore
	.global _switch_with_restore

; void switch_without_restore(char *cur_sp, char *next_sp, function entry);
_switch_without_restore:
	mov.l   er6,@-er7
	mov.l   er7,er6
	
	mov.l   er0,@-er7 ; save general registers
	mov.l   er1,@-er7
	mov.l   er2,@-er7
	mov.l   er3,@-er7
	mov.l   er4,@-er7
	mov.l   er5,@-er7
	mov.l   er6,@-er7
	mov.l   er7,@er0  ; save SP
	mov.l   er1,er7   ; switch SP
	jmp     @er2      ; jump!

; void switch_without_restore(char *cur_sp, char *next_sp);
_switch_with_restore:
	mov.l   er6,@-er7
	mov.l   er7,er6
	
	mov.l   er0,@-er7 ; save general registers
	mov.l   er1,@-er7
	mov.l   er2,@-er7
	mov.l   er3,@-er7
	mov.l   er4,@-er7
	mov.l   er5,@-er7
	mov.l   er6,@-er7
	mov.l	er7,@er0  ; save SP
	mov.l   er1,er7   ; switch SP
	mov.l	@er7+,er6 ; restore general registers
	mov.l	@er7+,er5
	mov.l	@er7+,er4
	mov.l	@er7+,er3
	mov.l	@er7+,er2
	mov.l	@er7+,er1
	mov.l	@er7+,er0
	rts/l   er6