xref: /kernel/linux/linux-5.10/arch/c6x/lib/divi.S (revision 8c2ecf20)
18c2ecf20Sopenharmony_ci;; SPDX-License-Identifier: GPL-2.0-or-later
28c2ecf20Sopenharmony_ci;;  Copyright 2010  Free Software Foundation, Inc.
38c2ecf20Sopenharmony_ci;;  Contributed by Bernd Schmidt <bernds@codesourcery.com>.
48c2ecf20Sopenharmony_ci;;
58c2ecf20Sopenharmony_ci
68c2ecf20Sopenharmony_ci#include <linux/linkage.h>
78c2ecf20Sopenharmony_ci
88c2ecf20Sopenharmony_ci	;; ABI considerations for the divide functions
98c2ecf20Sopenharmony_ci	;; The following registers are call-used:
108c2ecf20Sopenharmony_ci	;; __c6xabi_divi A0,A1,A2,A4,A6,B0,B1,B2,B4,B5
118c2ecf20Sopenharmony_ci	;; __c6xabi_divu A0,A1,A2,A4,A6,B0,B1,B2,B4
128c2ecf20Sopenharmony_ci	;; __c6xabi_remi A1,A2,A4,A5,A6,B0,B1,B2,B4
138c2ecf20Sopenharmony_ci	;; __c6xabi_remu A1,A4,A5,A7,B0,B1,B2,B4
148c2ecf20Sopenharmony_ci	;;
158c2ecf20Sopenharmony_ci	;; In our implementation, divu and remu are leaf functions,
168c2ecf20Sopenharmony_ci	;; while both divi and remi call into divu.
178c2ecf20Sopenharmony_ci	;; A0 is not clobbered by any of the functions.
188c2ecf20Sopenharmony_ci	;; divu does not clobber B2 either, which is taken advantage of
198c2ecf20Sopenharmony_ci	;; in remi.
208c2ecf20Sopenharmony_ci	;; divi uses B5 to hold the original return address during
218c2ecf20Sopenharmony_ci	;; the call to divu.
228c2ecf20Sopenharmony_ci	;; remi uses B2 and A5 to hold the input values during the
238c2ecf20Sopenharmony_ci	;; call to divu.  It stores B3 in on the stack.
248c2ecf20Sopenharmony_ci
258c2ecf20Sopenharmony_ci	.text
268c2ecf20Sopenharmony_ciENTRY(__c6xabi_divi)
278c2ecf20Sopenharmony_ci	call	.s2	__c6xabi_divu
288c2ecf20Sopenharmony_ci||	mv	.d2	B3, B5
298c2ecf20Sopenharmony_ci||	cmpgt	.l1	0, A4, A1
308c2ecf20Sopenharmony_ci||	cmpgt	.l2	0, B4, B1
318c2ecf20Sopenharmony_ci
328c2ecf20Sopenharmony_ci   [A1]	neg	.l1	A4, A4
338c2ecf20Sopenharmony_ci|| [B1]	neg	.l2	B4, B4
348c2ecf20Sopenharmony_ci||	xor	.s1x	A1, B1, A1
358c2ecf20Sopenharmony_ci   [A1] addkpc	.s2	_divu_ret, B3, 4
368c2ecf20Sopenharmony_ci_divu_ret:
378c2ecf20Sopenharmony_ci	neg	.l1	A4, A4
388c2ecf20Sopenharmony_ci||	mv	.l2	B3,B5
398c2ecf20Sopenharmony_ci||	ret	.s2	B5
408c2ecf20Sopenharmony_ci	nop		5
418c2ecf20Sopenharmony_ciENDPROC(__c6xabi_divi)
42