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arch/c6x/lib/remi.S 1.98 KB
09831ca73   Aurelien Jacquiot   C6X: library code
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  ;;  Copyright 2010  Free Software Foundation, Inc.
  ;;  Contributed by Bernd Schmidt <bernds@codesourcery.com>.
  ;;
  ;; This program is free software; you can redistribute it and/or modify
  ;; it under the terms of 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.
  ;;
  ;; This program 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 a copy of the GNU General Public License
  ;; along with this program; if not, write to the Free Software
  ;; Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  
  #include <linux/linkage.h>
  
  	;; ABI considerations for the divide functions
  	;; The following registers are call-used:
  	;; __c6xabi_divi A0,A1,A2,A4,A6,B0,B1,B2,B4,B5
  	;; __c6xabi_divu A0,A1,A2,A4,A6,B0,B1,B2,B4
  	;; __c6xabi_remi A1,A2,A4,A5,A6,B0,B1,B2,B4
  	;; __c6xabi_remu A1,A4,A5,A7,B0,B1,B2,B4
  	;;
  	;; In our implementation, divu and remu are leaf functions,
  	;; while both divi and remi call into divu.
  	;; A0 is not clobbered by any of the functions.
  	;; divu does not clobber B2 either, which is taken advantage of
  	;; in remi.
  	;; divi uses B5 to hold the original return address during
  	;; the call to divu.
  	;; remi uses B2 and A5 to hold the input values during the
  	;; call to divu.  It stores B3 in on the stack.
  
  	.text
  
  ENTRY(__c6xabi_remi)
  	stw	.d2t2	B3, *B15--[2]
  ||	cmpgt	.l1	0, A4, A1
  ||	cmpgt	.l2	0, B4, B2
  ||	mv	.s1	A4, A5
  ||	call	.s2	__c6xabi_divu
  
     [A1]	neg	.l1	A4, A4
  || [B2]	neg	.l2	B4, B4
  ||	xor	.s2x	B2, A1, B0
  ||	mv	.d2	B4, B2
  
     [B0]	addkpc	.s2	_divu_ret_1, B3, 1
    [!B0] addkpc	.s2	_divu_ret_2, B3, 1
  	nop	2
  _divu_ret_1:
  	neg	.l1	A4, A4
  _divu_ret_2:
  	ldw	.d2t2	*++B15[2], B3
  
  	mpy32	.m1x	A4, B2, A6
  	nop		3
  	ret	.s2	B3
  	sub	.l1	A5, A6, A4
  	nop	4
  ENDPROC(__c6xabi_remi)