V5/usr/source/s4/atan.s

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.globl	_atan,atan,retrn,savr5
_atan:
	mov	r5,-(sp)
	mov	sp,r5
	mov	r5,savr5
	movf	4(r5),fr0
	jsr	r5,atan
	clr	savr5
	jmp	retrn