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222 lines
5.0 KiB
222 lines
5.0 KiB
/*
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* File: arch/blackfin/lib/ins.S
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* Based on:
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* Author: Bas Vermeulen <bas@buyways.nl>
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*
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* Created: Tue Mar 22 15:27:24 CEST 2005
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* Description: Implementation of ins{bwl} for BlackFin processors using zero overhead loops.
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*
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* Modified:
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* Copyright 2004-2008 Analog Devices Inc.
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* Copyright (C) 2005 Bas Vermeulen, BuyWays BV <bas@buyways.nl>
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*
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* Bugs: 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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#include <linux/linkage.h>
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#include <asm/blackfin.h>
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.align 2
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/*
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* Reads on the Blackfin are speculative. In Blackfin terms, this means they
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* can be interrupted at any time (even after they have been issued on to the
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* external bus), and re-issued after the interrupt occurs.
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*
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* If a FIFO is sitting on the end of the read, it will see two reads,
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* when the core only sees one. The FIFO receives the read which is cancelled,
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* and not delivered to the core.
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*
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* To solve this, interrupts are turned off before reads occur to I/O space.
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* There are 3 versions of all these functions
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* - turns interrupts off every read (higher overhead, but lower latency)
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* - turns interrupts off every loop (low overhead, but longer latency)
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* - DMA version, which do not suffer from this issue. DMA versions have
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* different name (prefixed by dma_ ), and are located in
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* ../kernel/bfin_dma_5xx.c
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* Using the dma related functions are recommended for transfering large
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* buffers in/out of FIFOs.
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*/
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ENTRY(_insl)
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#ifdef CONFIG_BFIN_INS_LOWOVERHEAD
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P0 = R0; /* P0 = port */
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cli R3;
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P1 = R1; /* P1 = address */
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P2 = R2; /* P2 = count */
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SSYNC;
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LSETUP( .Llong_loop_s, .Llong_loop_e) LC0 = P2;
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.Llong_loop_s: R0 = [P0];
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[P1++] = R0;
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NOP;
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.Llong_loop_e: NOP;
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sti R3;
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RTS;
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#else
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P0 = R0; /* P0 = port */
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P1 = R1; /* P1 = address */
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P2 = R2; /* P2 = count */
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SSYNC;
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LSETUP( .Llong_loop_s, .Llong_loop_e) LC0 = P2;
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.Llong_loop_s:
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CLI R3;
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NOP; NOP; NOP;
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R0 = [P0];
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[P1++] = R0;
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.Llong_loop_e:
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STI R3;
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RTS;
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#endif
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ENDPROC(_insl)
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ENTRY(_insw)
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#ifdef CONFIG_BFIN_INS_LOWOVERHEAD
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P0 = R0; /* P0 = port */
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cli R3;
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P1 = R1; /* P1 = address */
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P2 = R2; /* P2 = count */
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SSYNC;
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LSETUP( .Lword_loop_s, .Lword_loop_e) LC0 = P2;
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.Lword_loop_s: R0 = W[P0];
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W[P1++] = R0;
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NOP;
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.Lword_loop_e: NOP;
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sti R3;
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RTS;
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#else
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P0 = R0; /* P0 = port */
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P1 = R1; /* P1 = address */
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P2 = R2; /* P2 = count */
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SSYNC;
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LSETUP( .Lword_loop_s, .Lword_loop_e) LC0 = P2;
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.Lword_loop_s:
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CLI R3;
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NOP; NOP; NOP;
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R0 = W[P0];
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W[P1++] = R0;
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.Lword_loop_e:
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STI R3;
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RTS;
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#endif
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ENDPROC(_insw)
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ENTRY(_insw_8)
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#ifdef CONFIG_BFIN_INS_LOWOVERHEAD
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P0 = R0; /* P0 = port */
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cli R3;
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P1 = R1; /* P1 = address */
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P2 = R2; /* P2 = count */
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SSYNC;
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LSETUP( .Lword8_loop_s, .Lword8_loop_e) LC0 = P2;
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.Lword8_loop_s: R0 = W[P0];
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B[P1++] = R0;
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R0 = R0 >> 8;
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B[P1++] = R0;
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NOP;
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.Lword8_loop_e: NOP;
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sti R3;
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RTS;
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#else
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P0 = R0; /* P0 = port */
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P1 = R1; /* P1 = address */
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P2 = R2; /* P2 = count */
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SSYNC;
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LSETUP( .Lword8_loop_s, .Lword8_loop_e) LC0 = P2;
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.Lword8_loop_s:
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CLI R3;
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NOP; NOP; NOP;
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R0 = W[P0];
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B[P1++] = R0;
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R0 = R0 >> 8;
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B[P1++] = R0;
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NOP;
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.Lword8_loop_e:
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STI R3;
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RTS;
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#endif
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ENDPROC(_insw_8)
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ENTRY(_insb)
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#ifdef CONFIG_BFIN_INS_LOWOVERHEAD
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P0 = R0; /* P0 = port */
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cli R3;
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P1 = R1; /* P1 = address */
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P2 = R2; /* P2 = count */
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SSYNC;
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LSETUP( .Lbyte_loop_s, .Lbyte_loop_e) LC0 = P2;
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.Lbyte_loop_s: R0 = B[P0];
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B[P1++] = R0;
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NOP;
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.Lbyte_loop_e: NOP;
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sti R3;
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RTS;
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#else
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P0 = R0; /* P0 = port */
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P1 = R1; /* P1 = address */
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P2 = R2; /* P2 = count */
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SSYNC;
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LSETUP( .Lbyte_loop_s, .Lbyte_loop_e) LC0 = P2;
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.Lbyte_loop_s:
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CLI R3;
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NOP; NOP; NOP;
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R0 = B[P0];
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B[P1++] = R0;
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.Lbyte_loop_e:
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STI R3;
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RTS;
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#endif
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ENDPROC(_insb)
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ENTRY(_insl_16)
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#ifdef CONFIG_BFIN_INS_LOWOVERHEAD
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P0 = R0; /* P0 = port */
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cli R3;
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P1 = R1; /* P1 = address */
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P2 = R2; /* P2 = count */
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SSYNC;
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LSETUP( .Llong16_loop_s, .Llong16_loop_e) LC0 = P2;
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.Llong16_loop_s: R0 = [P0];
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W[P1++] = R0;
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R0 = R0 >> 16;
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W[P1++] = R0;
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NOP;
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.Llong16_loop_e: NOP;
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sti R3;
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RTS;
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#else
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P0 = R0; /* P0 = port */
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P1 = R1; /* P1 = address */
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P2 = R2; /* P2 = count */
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SSYNC;
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LSETUP( .Llong16_loop_s, .Llong16_loop_e) LC0 = P2;
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.Llong16_loop_s:
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CLI R3;
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NOP; NOP; NOP;
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R0 = [P0];
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W[P1++] = R0;
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R0 = R0 >> 16;
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W[P1++] = R0;
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.Llong16_loop_e:
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STI R3;
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RTS;
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#endif
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ENDPROC(_insl_16)
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