udivsi3_i4i.S revision 1.2
1 1.2 uwe /* $NetBSD: udivsi3_i4i.S,v 1.2 2011/08/05 02:00:25 uwe Exp $ */ 2 1.1 uwe 3 1.1 uwe /*- 4 1.1 uwe * Copyright (c) 1990 The Regents of the University of California. 5 1.1 uwe * All rights reserved. 6 1.1 uwe * 7 1.1 uwe * This code is derived from software contributed to Berkeley by 8 1.1 uwe * William Jolitz. 9 1.1 uwe * 10 1.1 uwe * Redistribution and use in source and binary forms, with or without 11 1.1 uwe * modification, are permitted provided that the following conditions 12 1.1 uwe * are met: 13 1.1 uwe * 1. Redistributions of source code must retain the above copyright 14 1.1 uwe * notice, this list of conditions and the following disclaimer. 15 1.1 uwe * 2. Redistributions in binary form must reproduce the above copyright 16 1.1 uwe * notice, this list of conditions and the following disclaimer in the 17 1.1 uwe * documentation and/or other materials provided with the distribution. 18 1.1 uwe * 3. Neither the name of the University nor the names of its contributors 19 1.1 uwe * may be used to endorse or promote products derived from this software 20 1.1 uwe * without specific prior written permission. 21 1.1 uwe * 22 1.1 uwe * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 1.1 uwe * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 1.1 uwe * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 1.1 uwe * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 1.1 uwe * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 1.1 uwe * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 1.1 uwe * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 1.1 uwe * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 1.1 uwe * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 1.1 uwe * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 1.1 uwe * SUCH DAMAGE. 33 1.1 uwe * 34 1.1 uwe * from: @(#)udivsi3.s 5.1 (Berkeley) 5/15/90 35 1.1 uwe */ 36 1.1 uwe 37 1.1 uwe #include <machine/asm.h> 38 1.1 uwe #if defined(LIBC_SCCS) 39 1.2 uwe RCSID("$NetBSD: udivsi3_i4i.S,v 1.2 2011/08/05 02:00:25 uwe Exp $") 40 1.1 uwe #endif 41 1.1 uwe 42 1.1 uwe /* 43 1.1 uwe * IMPOTANT: This function is special. 44 1.1 uwe * 45 1.2 uwe * This function is an auxiliary "millicode" function that is 46 1.2 uwe * referenced by the code generated by gcc for unsigned integer 47 1.2 uwe * division. But gcc does NOT treat a call to this function as an 48 1.2 uwe * ordinary function call - it can clobber only R1, MACL and MACH. 49 1.2 uwe * 50 1.2 uwe * See the definition of "udivsi3_i4_int" in gcc/config/sh/sh.md 51 1.2 uwe * 52 1.2 uwe * As the consequence this function cannot be called via any 53 1.2 uwe * indirection that assumes normal calling convention: 54 1.2 uwe * 55 1.2 uwe * . cannot have _PROF_PROLOGUE 56 1.2 uwe * . cannot be called via PLT (not relevant for kernel) 57 1.2 uwe * 58 1.2 uwe * XXX: uwe: Older gcc used __udivsi3; newer uses __udivsi3_i4i - a 59 1.2 uwe * heavily tuned version that is NOT compatible with __udivsi3 because 60 1.2 uwe * it clobbers different registers. We don't want to link the kernel 61 1.2 uwe * against libgcc and we don't have resources to write heavily tuned 62 1.2 uwe * version ourselves, so clone __udivsi3 but adjust the code to 63 1.2 uwe * conform to the __udivsi3_i4i clobber spec. 64 1.1 uwe */ 65 1.1 uwe 66 1.1 uwe 67 1.1 uwe #ifdef __ELF__ 68 1.1 uwe .hidden __udivsi3_i4i 69 1.1 uwe #endif 70 1.1 uwe 71 1.1 uwe 72 1.1 uwe /* r0 <= r4 / r5 */ 73 1.1 uwe NENTRY(__udivsi3_i4i) 74 1.1 uwe tst r5, r5 75 1.1 uwe bt .L_div_by_zero 76 1.1 uwe 77 1.1 uwe mov r4, r1 ! cannot clobber r4 in this version 78 1.1 uwe mov #0, r0 79 1.1 uwe div0u 80 1.1 uwe #define DIVSTEP rotcl r1; div1 r5, r0 81 1.1 uwe /* repeat 32 times */ 82 1.1 uwe DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; 83 1.1 uwe DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; 84 1.1 uwe DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; 85 1.1 uwe DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; 86 1.1 uwe #undef DIVSTEP 87 1.1 uwe rotcl r1 88 1.1 uwe 89 1.1 uwe rts 90 1.1 uwe mov r1, r0 91 1.1 uwe 92 1.1 uwe .L_div_by_zero: 93 1.1 uwe rts 94 1.1 uwe mov #0, r0 95
Indexes created Wed Oct 01 18:09:54 GMT 2025