;; 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_remu) ;; The ABI seems designed to prevent these functions calling each other, ;; so we duplicate most of the divsi3 code here. mv .s2x A4, B1 lmbd .l2 1, B4, B1 || [!B1] b .s2 B3 ; RETURN A || [!B1] mvk .d2 1, B4 mv .l1x B1, A7 || shl .s2 B4, B1, B4 cmpltu .l1x A4, B4, A1 [!A1] sub .l1x A4, B4, A4 shru .s2 B4, 1, B4 _remu_loop: cmpgt .l2 B1, 7, B0 || [B1] subc .l1x A4,B4,A4 || [B1] add .s2 -1, B1, B1 ;; RETURN A may happen here (note: must happen before the next branch) [B1] subc .l1x A4,B4,A4 || [B1] add .s2 -1, B1, B1 || [B0] b .s1 _remu_loop [B1] subc .l1x A4,B4,A4 || [B1] add .s2 -1, B1, B1 [B1] subc .l1x A4,B4,A4 || [B1] add .s2 -1, B1, B1 [B1] subc .l1x A4,B4,A4 || [B1] add .s2 -1, B1, B1 [B1] subc .l1x A4,B4,A4 || [B1] add .s2 -1, B1, B1 [B1] subc .l1x A4,B4,A4 || [B1] add .s2 -1, B1, B1 ;; loop backwards branch happens here ret .s2 B3 [B1] subc .l1x A4,B4,A4 || [B1] add .s2 -1, B1, B1 [B1] subc .l1x A4,B4,A4 extu .s1 A4, A7, A4 nop 2 ENDPROC(__c6xabi_remu)