File:  [Power 6/32 Unix Tahoe 4.2BSD] / cci / sys / tahoe / Ksfnorm.x
Revision 1.1.1.1 (vendor branch): download - view: text, annotated - select for diffs
Sun Jul 28 12:24:19 2019 UTC (6 years, 11 months ago) by root
Branches: bsd, MAIN
CVS tags: v12b, v121, HEAD
Power 6/32 Unix version 1.2b


#include 	"fp.h"
#include 	"fp_in_krnl.h"


	.text
	.globl	Ksfnorm		# Ksfnorm(hfs)
Ksfnorm:	.word	0x007c
	clrl	r1
	movl	r0,r4		/* copy to temporary. */
	jeql	retzero
	clrl	r3		/* r3 - pos of m.s.b */
inr00:	ffs	r4,r6
	incl	r6
	addl2	r6,r3
	shrl	r6,r4,r4
	jneq	inr00

cmpshift:
				/* compute the shift (r4). */
	subl3	r3,$HID_POS,r4
	jlss	shiftr		/* if less then zero we shift right. */
	shll	r4,r0,r0	/* else we shift left. */
	subl2	r4,r2		/* uodate exponent. */
	jleq	underflow	/* if less then 0 (biased) it is underflow. */
	jmp	combine		/* go to combine exponent and fraction. */
shiftr:
	mnegl	r4,r4
	shrl	r4,r0,r0	/* shift right. */
	addl2	r4,r2		/* update exponent */
	cmpl	r2,$256
	jgeq	overflow	/* check for overflow. */
combine:
	andl2	$CLEARHID,r0	/* clear the hidden bit. */
	shal	$EXPSHIFT,r2,r2	/* shift the exponent to its proper place. */
	orl2	r2,r0
	ret

underflow:
	orl2	$HFS_UNDF,*4(fp)	
	ret

overflow:
	orl2	$HFS_OVF,*4(fp)
	ret
retzero:
	clrl	r0
	ret
	

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