glibc/sysdeps/hppa/sub_n.S

;! HP-PA  __mpn_sub_n -- Subtract two limb vectors of the same length > 0 and
;! store difference in a third limb vector.

;! Copyright (C) 1992-2020 Free Software Foundation, Inc.

;! This file is part of the GNU MP Library.

;! The GNU MP Library is free software; you can redistribute it and/or modify
;! it under the terms of the GNU Lesser General Public License as published by
;! the Free Software Foundation; either version 2.1 of the License, or (at your
;! option) any later version.

;! The GNU MP Library is distributed in the hope that it will be useful, but
;! WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
;! or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
;! License for more details.

;! You should have received a copy of the GNU Lesser General Public License
;! along with the GNU MP Library.  If not, see
;! <https://www.gnu.org/licenses/>.


;! INPUT PARAMETERS
;! res_ptr	gr26
;! s1_ptr	gr25
;! s2_ptr	gr24
;! size		gr23

;! One might want to unroll this as for other processors, but it turns
;! out that the data cache contention after a store makes such
;! unrolling useless.  We can't come under 5 cycles/limb anyway.

	.text
	.export		__mpn_sub_n
__mpn_sub_n:
	.proc
	.callinfo	frame=0,no_calls
	.entry

	ldws,ma		4(%r25),%r21
	ldws,ma		4(%r24),%r20

	addib,=		-1,%r23,L$end	;! check for (SIZE == 1)
	 sub		%r21,%r20,%r28	;! subtract first limbs ignoring cy

L$loop:	ldws,ma		4(%r25),%r21
	ldws,ma		4(%r24),%r20
	stws,ma		%r28,4(%r26)
	addib,<>	-1,%r23,L$loop
	 subb		%r21,%r20,%r28

L$end:	stws		%r28,0(%r26)
	addc		%r0,%r0,%r28
	bv		0(%r2)
	 subi		1,%r28,%r28

	.exit
	.procend