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https://github.com/AsahiLinux/u-boot
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96 lines
2.5 KiB
ArmAsm
96 lines
2.5 KiB
ArmAsm
/*
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* File: memmove.S
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*
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* Copyright 2004-2007 Analog Devices Inc.
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* Enter bugs at http://blackfin.uclinux.org/
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program 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
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see the file COPYING, or write
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* to the Free Software Foundation, Inc.,
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* 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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.align 2
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/*
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* C Library function MEMMOVE
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* R0 = To Address (leave unchanged to form result)
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* R1 = From Address
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* R2 = count
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* Data may overlap
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*/
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.globl _memmove;
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.type _memmove, STT_FUNC;
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_memmove:
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I1 = P3;
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P0 = R0; /* P0 = To address */
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P3 = R1; /* P3 = From Address */
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P2 = R2 ; /* P2 = count */
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CC = P2 == 0; /* Check zero count*/
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IF CC JUMP .Lfinished; /* very unlikely */
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CC = R1 < R0 (IU); /* From < To */
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IF !CC JUMP .Lno_overlap;
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R3 = R1 + R2;
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CC = R0 <= R3 (IU); /* (From+len) >= To */
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IF CC JUMP .Loverlap;
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.Lno_overlap:
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R3 = 11;
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CC = R2 <= R3;
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IF CC JUMP .Lbytes;
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R3 = R1 | R0; /* OR addresses together */
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R3 <<= 30; /* check bottom two bits */
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CC = AZ; /* AZ set if zero.*/
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IF !CC JUMP .Lbytes ; /* Jump if addrs not aligned.*/
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I0 = P3;
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P1 = P2 >> 2; /* count = n/4 */
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P1 += -1;
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R3 = 3;
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R2 = R2 & R3; /* remainder */
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P2 = R2; /* set remainder */
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R1 = [I0++];
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LSETUP (.Lquad_loop , .Lquad_loop) LC0=P1;
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.Lquad_loop: MNOP || [P0++] = R1 || R1 = [I0++];
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[P0++] = R1;
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CC = P2 == 0; /* any remaining bytes? */
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P3 = I0; /* Ammend P3 to updated ptr. */
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IF !CC JUMP .Lbytes;
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P3 = I1;
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RTS;
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.Lbytes: LSETUP (.Lbyte2_s , .Lbyte2_e) LC0=P2;
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.Lbyte2_s: R1 = B[P3++](Z);
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.Lbyte2_e: B[P0++] = R1;
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.Lfinished: P3 = I1;
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RTS;
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.Loverlap:
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P2 += -1;
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P0 = P0 + P2;
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P3 = P3 + P2;
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R1 = B[P3--] (Z);
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CC = P2 == 0;
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IF CC JUMP .Lno_loop;
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LSETUP (.Lol_s, .Lol_e) LC0 = P2;
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.Lol_s: B[P0--] = R1;
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.Lol_e: R1 = B[P3--] (Z);
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.Lno_loop: B[P0] = R1;
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P3 = I1;
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RTS;
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.size _memmove, .-_memmove
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