1;; Copyright 2011 Free Software Foundation, Inc. 2;; Contributed by Bernd Schmidt <bernds@codesourcery.com>. 3;; 4;; This program is free software; you can redistribute it and/or modify 5;; it under the terms of the GNU General Public License as published by 6;; the Free Software Foundation; either version 2 of the License, or 7;; (at your option) any later version. 8;; 9;; This program is distributed in the hope that it will be useful, 10;; but WITHOUT ANY WARRANTY; without even the implied warranty of 11;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12;; GNU General Public License for more details. 13;; 14;; You should have received a copy of the GNU General Public License 15;; along with this program; if not, write to the Free Software 16;; Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. 17 18#include <linux/linkage.h> 19 20 .text 21ENTRY(__c6xabi_divremu) 22 ;; We use a series of up to 31 subc instructions. First, we find 23 ;; out how many leading zero bits there are in the divisor. This 24 ;; gives us both a shift count for aligning (shifting) the divisor 25 ;; to the, and the number of times we have to execute subc. 26 27 ;; At the end, we have both the remainder and most of the quotient 28 ;; in A4. The top bit of the quotient is computed first and is 29 ;; placed in A2. 30 31 ;; Return immediately if the dividend is zero. Setting B4 to 1 32 ;; is a trick to allow us to leave the following insns in the jump 33 ;; delay slot without affecting the result. 34 mv .s2x A4, B1 35 36 [b1] lmbd .l2 1, B4, B1 37||[!b1] b .s2 B3 ; RETURN A 38||[!b1] mvk .d2 1, B4 39 40||[!b1] zero .s1 A5 41 mv .l1x B1, A6 42|| shl .s2 B4, B1, B4 43 44 ;; The loop performs a maximum of 28 steps, so we do the 45 ;; first 3 here. 46 cmpltu .l1x A4, B4, A2 47 [!A2] sub .l1x A4, B4, A4 48|| shru .s2 B4, 1, B4 49|| xor .s1 1, A2, A2 50 51 shl .s1 A2, 31, A2 52|| [b1] subc .l1x A4,B4,A4 53|| [b1] add .s2 -1, B1, B1 54 [b1] subc .l1x A4,B4,A4 55|| [b1] add .s2 -1, B1, B1 56 57 ;; RETURN A may happen here (note: must happen before the next branch) 58__divremu0: 59 cmpgt .l2 B1, 7, B0 60|| [b1] subc .l1x A4,B4,A4 61|| [b1] add .s2 -1, B1, B1 62 [b1] subc .l1x A4,B4,A4 63|| [b1] add .s2 -1, B1, B1 64|| [b0] b .s1 __divremu0 65 [b1] subc .l1x A4,B4,A4 66|| [b1] add .s2 -1, B1, B1 67 [b1] subc .l1x A4,B4,A4 68|| [b1] add .s2 -1, B1, B1 69 [b1] subc .l1x A4,B4,A4 70|| [b1] add .s2 -1, B1, B1 71 [b1] subc .l1x A4,B4,A4 72|| [b1] add .s2 -1, B1, B1 73 [b1] subc .l1x A4,B4,A4 74|| [b1] add .s2 -1, B1, B1 75 ;; loop backwards branch happens here 76 77 ret .s2 B3 78|| mvk .s1 32, A1 79 sub .l1 A1, A6, A6 80|| extu .s1 A4, A6, A5 81 shl .s1 A4, A6, A4 82 shru .s1 A4, 1, A4 83|| sub .l1 A6, 1, A6 84 or .l1 A2, A4, A4 85 shru .s1 A4, A6, A4 86 nop 87ENDPROC(__c6xabi_divremu) 88