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Diffstat (limited to 'arch/arm/lib/memset_rpi.S')
| -rw-r--r-- | arch/arm/lib/memset_rpi.S | 128 |
1 files changed, 128 insertions, 0 deletions
diff --git a/arch/arm/lib/memset_rpi.S b/arch/arm/lib/memset_rpi.S new file mode 100644 index 000000000000..e8469cecabc1 --- /dev/null +++ b/arch/arm/lib/memset_rpi.S @@ -0,0 +1,128 @@ +/* +Copyright (c) 2013, Raspberry Pi Foundation +Copyright (c) 2013, RISC OS Open Ltd +All rights reserved. + +Redistribution and use in source and binary forms, with or without +modification, are permitted provided that the following conditions are met: + * Redistributions of source code must retain the above copyright + notice, this list of conditions and the following disclaimer. + * Redistributions in binary form must reproduce the above copyright + notice, this list of conditions and the following disclaimer in the + documentation and/or other materials provided with the distribution. + * Neither the name of the copyright holder nor the + names of its contributors may be used to endorse or promote products + derived from this software without specific prior written permission. + +THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND +ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED +WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE +DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY +DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES +(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; +LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND +ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS +SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. +*/ + +#include <linux/linkage.h> +#include "arm-mem.h" + +/* Prevent the stack from becoming executable */ +#if defined(__linux__) && defined(__ELF__) +.section .note.GNU-stack,"",%progbits +#endif + + .text + .arch armv6 + .object_arch armv4 + .arm + .altmacro + .p2align 2 + +/* + * void *memset(void *s, int c, size_t n); + * On entry: + * a1 = pointer to buffer to fill + * a2 = byte pattern to fill with (caller-narrowed) + * a3 = number of bytes to fill + * On exit: + * a1 preserved + */ +ENTRY(mmioset) +ENTRY(memset) +ENTRY(__memset32) +ENTRY(__memset64) + + S .req a1 + DAT0 .req a2 + N .req a3 + DAT1 .req a4 + DAT2 .req ip + DAT3 .req lr + + orr DAT0, DAT0, DAT0, lsl #8 + push {S, lr} + orr DAT0, DAT0, DAT0, lsl #16 + mov DAT1, DAT0 + + /* See if we're guaranteed to have at least one 16-byte aligned 16-byte write */ + cmp N, #31 + blo 170f + +161: sub N, N, #16 /* simplifies inner loop termination */ + /* Leading words and bytes */ + tst S, #15 + beq 164f + rsb DAT3, S, #0 /* bits 0-3 = number of leading bytes until aligned */ + movs DAT2, DAT3, lsl #31 + submi N, N, #1 + strmib DAT0, [S], #1 + subcs N, N, #2 + strcsh DAT0, [S], #2 + movs DAT2, DAT3, lsl #29 + submi N, N, #4 + strmi DAT0, [S], #4 + subcs N, N, #8 + stmcsia S!, {DAT0, DAT1} +164: /* Delayed set up of DAT2 and DAT3 so we could use them as scratch registers above */ + mov DAT2, DAT0 + mov DAT3, DAT0 + /* Now the inner loop of 16-byte stores */ +165: stmia S!, {DAT0, DAT1, DAT2, DAT3} + subs N, N, #16 + bhs 165b +166: /* Trailing words and bytes */ + movs N, N, lsl #29 + stmcsia S!, {DAT0, DAT1} + strmi DAT0, [S], #4 + movs N, N, lsl #2 + strcsh DAT0, [S], #2 + strmib DAT0, [S] +199: pop {S, pc} + +170: /* Short case */ + mov DAT2, DAT0 + mov DAT3, DAT0 + tst S, #3 + beq 174f +172: subs N, N, #1 + blo 199b + strb DAT0, [S], #1 + tst S, #3 + bne 172b +174: tst N, #16 + stmneia S!, {DAT0, DAT1, DAT2, DAT3} + b 166b + + .unreq S + .unreq DAT0 + .unreq N + .unreq DAT1 + .unreq DAT2 + .unreq DAT3 +ENDPROC(__memset64) +ENDPROC(__memset32) +ENDPROC(memset) +ENDPROC(mmioset) |