Annotation of sys/lib/libkern/arch/sh/udivsi3.S, Revision 1.1
1.1 ! nbrk 1: /* $NetBSD: udivsi3.S,v 1.7 2006/05/22 20:56:44 uwe Exp $ */
! 2:
! 3: /*-
! 4: * Copyright (c) 1990 The Regents of the University of California.
! 5: * All rights reserved.
! 6: *
! 7: * This code is derived from software contributed to Berkeley by
! 8: * William Jolitz.
! 9: *
! 10: * Redistribution and use in source and binary forms, with or without
! 11: * modification, are permitted provided that the following conditions
! 12: * are met:
! 13: * 1. Redistributions of source code must retain the above copyright
! 14: * notice, this list of conditions and the following disclaimer.
! 15: * 2. Redistributions in binary form must reproduce the above copyright
! 16: * notice, this list of conditions and the following disclaimer in the
! 17: * documentation and/or other materials provided with the distribution.
! 18: * 3. Neither the name of the University nor the names of its contributors
! 19: * may be used to endorse or promote products derived from this software
! 20: * without specific prior written permission.
! 21: *
! 22: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
! 23: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
! 24: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
! 25: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
! 26: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
! 27: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
! 28: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
! 29: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
! 30: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
! 31: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
! 32: * SUCH DAMAGE.
! 33: *
! 34: * from: @(#)udivsi3.s 5.1 (Berkeley) 5/15/90
! 35: */
! 36:
! 37: #include <machine/asm.h>
! 38:
! 39: /*
! 40: * IMPORTANT: This function is special.
! 41: *
! 42: * This function is an auxiliary function that is referenced by the
! 43: * code generated by gcc for integer division. But gcc does NOT treat
! 44: * a call to this function as an ordinary function call w.r.t. the set
! 45: * of register this call clobbers. See the definition of "udivsi3_i1"
! 46: * in gcc/config/sh/sh.md.
! 47: *
! 48: * Any call to this function MUST NOT clobber any registers besides r4
! 49: * and r0, where the result is returned. At the time of the call the
! 50: * r4 contains the first argument, so we are only left with r0, and we
! 51: * cannot do anything meaningful using only one register. The
! 52: * consequences are:
! 53: *
! 54: * . this function cannot have _PROF_PROLOGUE
! 55: * . this function cannot be called via PLT
! 56: */
! 57:
! 58:
! 59: /* r0 <= r4 / r5 */
! 60: NENTRY(__udivsi3)
! 61: tst r5, r5
! 62: bt div_by_zero
! 63:
! 64: mov #0, r0
! 65: div0u
! 66: #define DIVSTEP rotcl r4; div1 r5, r0
! 67: /* repeat 32 times */
! 68: DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP;
! 69: DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP;
! 70: DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP;
! 71: DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP;
! 72: #undef DIVSTEP
! 73: rotcl r4
! 74:
! 75: rts
! 76: mov r4, r0
! 77:
! 78: div_by_zero:
! 79: #ifdef _KERNEL
! 80: rts
! 81: mov #0, r0
! 82: #else
! 83: mov.l r14, @-r15
! 84: sts.l pr, @-r15
! 85: mov r15, r14
! 86:
! 87: mov.l L_raise, r1
! 88: #ifdef PIC
! 89: 1: bsrf r1
! 90: #else
! 91: jsr @r1
! 92: #endif
! 93: mov #8, r4 /* delay slot. 8 <- SIGFPE. */
! 94: mov #0, r0
! 95:
! 96: lds.l @r15+, pr
! 97: rts
! 98: mov.l @r15+, r14
! 99:
! 100: .align 2
! 101: L_raise:
! 102: #ifdef PIC
! 103: .long _C_LABEL(raise)-(1b+4)
! 104: #else
! 105: .long _C_LABEL(raise)
! 106: #endif
! 107: #endif
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