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84 lines
2.6 KiB
ArmAsm
84 lines
2.6 KiB
ArmAsm
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/* Copyright (C) 2002 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Hartvig Ekner <hartvige@mips.com>, 2002.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA. */
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#include <sysdep.h>
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#include <endian.h>
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/* void *memset(void *s, int c, size_t n).
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This routine could be optimized further for MIPS64, but this is left
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as an exercise for the future. When it is done, the file should be kept
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as a sisterfile to this one, and placed in the sysdeps/mips/mips64
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directory. */
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#if __BYTE_ORDER == __BIG_ENDIAN
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# define SWHI swl /* high part is left in big-endian */
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#else
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# define SWHI swr /* high part is right in little-endian */
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#endif
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ENTRY (memset)
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.set noreorder
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slti t1, a2, 8 # Less than 8?
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bne t1, zero, $last8
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move v0, a0 # Setup exit value before too late
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beq a1, zero, $ueven # If zero pattern, no need to extend
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andi a1, 0xff # Avoid problems with bogus arguments
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sll t0, a1, 8
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or a1, t0
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sll t0, a1, 16
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or a1, t0 # a1 is now pattern in full word
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$ueven: subu t0, zero, a0 # Unaligned address?
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andi t0, 0x3
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beq t0, zero, $chkw
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subu a2, t0
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SWHI a1, 0(a0) # Yes, handle first unaligned part
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addu a0, t0 # Now both a0 and a2 are updated
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$chkw: andi t0, a2, 0x7 # Enough left for one loop iteration?
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beq t0, a2, $chkl
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subu a3, a2, t0
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addu a3, a0 # a3 is last loop address +1
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move a2, t0 # a2 is now # of bytes left after loop
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$loopw: addiu a0, 8 # Handle 2 words pr. iteration
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sw a1, -8(a0)
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bne a0, a3, $loopw
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sw a1, -4(a0)
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$chkl: andi t0, a2, 0x4 # Check if there is at least a full
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beq t0, zero, $last8 # word remaining after the loop
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subu a2, t0
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sw a1, 0(a0) # Yes...
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addiu a0, 4
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$last8: blez a2, $exit # Handle last 8 bytes (if cnt>0)
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addu a3, a2, a0 # a3 is last address +1
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$lst8l: addiu a0, 1
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bne a0, a3, $lst8l
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sb a1, -1(a0)
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$exit: j ra # Bye, bye
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nop
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.set reorder
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END (memset)
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