xref: /OK3568_Linux_fs/kernel/arch/c6x/lib/remi.S (revision 4882a59341e53eb6f0b4789bf948001014eff981)
1*4882a593Smuzhiyun;; SPDX-License-Identifier: GPL-2.0-or-later
2*4882a593Smuzhiyun;;  Copyright 2010  Free Software Foundation, Inc.
3*4882a593Smuzhiyun;;  Contributed by Bernd Schmidt <bernds@codesourcery.com>.
4*4882a593Smuzhiyun;;
5*4882a593Smuzhiyun
6*4882a593Smuzhiyun#include <linux/linkage.h>
7*4882a593Smuzhiyun
8*4882a593Smuzhiyun	;; ABI considerations for the divide functions
9*4882a593Smuzhiyun	;; The following registers are call-used:
10*4882a593Smuzhiyun	;; __c6xabi_divi A0,A1,A2,A4,A6,B0,B1,B2,B4,B5
11*4882a593Smuzhiyun	;; __c6xabi_divu A0,A1,A2,A4,A6,B0,B1,B2,B4
12*4882a593Smuzhiyun	;; __c6xabi_remi A1,A2,A4,A5,A6,B0,B1,B2,B4
13*4882a593Smuzhiyun	;; __c6xabi_remu A1,A4,A5,A7,B0,B1,B2,B4
14*4882a593Smuzhiyun	;;
15*4882a593Smuzhiyun	;; In our implementation, divu and remu are leaf functions,
16*4882a593Smuzhiyun	;; while both divi and remi call into divu.
17*4882a593Smuzhiyun	;; A0 is not clobbered by any of the functions.
18*4882a593Smuzhiyun	;; divu does not clobber B2 either, which is taken advantage of
19*4882a593Smuzhiyun	;; in remi.
20*4882a593Smuzhiyun	;; divi uses B5 to hold the original return address during
21*4882a593Smuzhiyun	;; the call to divu.
22*4882a593Smuzhiyun	;; remi uses B2 and A5 to hold the input values during the
23*4882a593Smuzhiyun	;; call to divu.  It stores B3 in on the stack.
24*4882a593Smuzhiyun
25*4882a593Smuzhiyun	.text
26*4882a593Smuzhiyun
27*4882a593SmuzhiyunENTRY(__c6xabi_remi)
28*4882a593Smuzhiyun	stw	.d2t2	B3, *B15--[2]
29*4882a593Smuzhiyun||	cmpgt	.l1	0, A4, A1
30*4882a593Smuzhiyun||	cmpgt	.l2	0, B4, B2
31*4882a593Smuzhiyun||	mv	.s1	A4, A5
32*4882a593Smuzhiyun||	call	.s2	__c6xabi_divu
33*4882a593Smuzhiyun
34*4882a593Smuzhiyun   [A1]	neg	.l1	A4, A4
35*4882a593Smuzhiyun|| [B2]	neg	.l2	B4, B4
36*4882a593Smuzhiyun||	xor	.s2x	B2, A1, B0
37*4882a593Smuzhiyun||	mv	.d2	B4, B2
38*4882a593Smuzhiyun
39*4882a593Smuzhiyun   [B0]	addkpc	.s2	_divu_ret_1, B3, 1
40*4882a593Smuzhiyun  [!B0] addkpc	.s2	_divu_ret_2, B3, 1
41*4882a593Smuzhiyun	nop	2
42*4882a593Smuzhiyun_divu_ret_1:
43*4882a593Smuzhiyun	neg	.l1	A4, A4
44*4882a593Smuzhiyun_divu_ret_2:
45*4882a593Smuzhiyun	ldw	.d2t2	*++B15[2], B3
46*4882a593Smuzhiyun
47*4882a593Smuzhiyun	mpy32	.m1x	A4, B2, A6
48*4882a593Smuzhiyun	nop		3
49*4882a593Smuzhiyun	ret	.s2	B3
50*4882a593Smuzhiyun	sub	.l1	A5, A6, A4
51*4882a593Smuzhiyun	nop	4
52*4882a593SmuzhiyunENDPROC(__c6xabi_remi)
53