; mc88100 mpn_add_n -- Add two limb vectors of the same length > 0 and store

; sum in a third limb vector.

; Copyright 1992, 1994, 1995, 2000 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 either:

;

;    * the GNU Lesser General Public License as published by the Free

;      Software Foundation; either version 3 of the License, or (at your

;      option) any later version.

;

;  or

;

;    * the GNU General Public License as published by the Free Software

;      Foundation; either version 2 of the License, or (at your option) any

;      later version.

;

;  or both in parallel, as here.

;

;  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 General Public License

;  for more details.

;

;  You should have received copies of the GNU General Public License and the

;  GNU Lesser General Public License along with the GNU MP Library.  If not,

;  see https://www.gnu.org/licenses/.

; INPUT PARAMETERS

; res_ptr	r2

; s1_ptr	r3

; s2_ptr	r4

; size		r5

; This code has been optimized to run one instruction per clock, avoiding

; load stalls and writeback contention.  As a result, the instruction

; order is not always natural.

; The speed is about 4.6 clocks/limb + 18 clocks/limb-vector on an 88100,

; but on the 88110, it seems to run much slower, 6.6 clocks/limb.

	text

	align	 16

	global	 ___gmpn_add_n

___gmpn_add_n:

	ld	r6,r3,0			; read first limb from s1_ptr

	extu	r10,r5,3

	ld	r7,r4,0			; read first limb from s2_ptr

	subu.co	r5,r0,r5		; (clear carry as side effect)

	mak	r5,r5,3<4>

	bcnd	eq0,r5,Lzero

	or	r12,r0,lo16(Lbase)

	or.u	r12,r12,hi16(Lbase)

	addu	r12,r12,r5		; r12 is address for entering in loop

	extu	r5,r5,2			; divide by 4

	subu	r2,r2,r5		; adjust res_ptr

	subu	r3,r3,r5		; adjust s1_ptr

	subu	r4,r4,r5		; adjust s2_ptr

	or	r8,r6,r0

	jmp.n	r12

	 or	r9,r7,r0

Loop:	addu	r3,r3,32

	st	r8,r2,28

	addu	r4,r4,32

	ld	r6,r3,0

	addu	r2,r2,32

	ld	r7,r4,0

Lzero:	subu	r10,r10,1		; add 0 + 8r limbs (adj loop cnt)

Lbase:	ld	r8,r3,4

	addu.cio r6,r6,r7

	ld	r9,r4,4

	st	r6,r2,0

	ld	r6,r3,8			; add 7 + 8r limbs

	addu.cio r8,r8,r9

	ld	r7,r4,8

	st	r8,r2,4

	ld	r8,r3,12		; add 6 + 8r limbs

	addu.cio r6,r6,r7

	ld	r9,r4,12

	st	r6,r2,8

	ld	r6,r3,16		; add 5 + 8r limbs

	addu.cio r8,r8,r9

	ld	r7,r4,16

	st	r8,r2,12

	ld	r8,r3,20		; add 4 + 8r limbs

	addu.cio r6,r6,r7

	ld	r9,r4,20

	st	r6,r2,16

	ld	r6,r3,24		; add 3 + 8r limbs

	addu.cio r8,r8,r9

	ld	r7,r4,24

	st	r8,r2,20

	ld	r8,r3,28		; add 2 + 8r limbs

	addu.cio r6,r6,r7

	ld	r9,r4,28

	st	r6,r2,24

	bcnd.n	ne0,r10,Loop		; add 1 + 8r limbs

	 addu.cio r8,r8,r9

	st	r8,r2,28		; store most significant limb

	jmp.n	 r1

	 addu.ci r2,r0,r0		; return carry-out from most sign. limb