patch.s

/*
 * Copyright (c) 2015 Toni Spets <toni.spets@iki.fi>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

.macro memset start, value, end
    .section .patch,"d0"
    .long (\start)
    .long (\end) - (\start)
    .fill (\end) - (\start), 1, (\value)
.endm

.macro memsjmp src, dst
    .section .patch,"d0"
    .long (\src)
    .long 2
    .byte 0xEB
    .byte (\dst) - (\src) - 2
.endm

.macro memljmp src, dst
    .section .patch,"d0"
    .long (\src)
    .long 5
    .byte 0xE9
    .long (\dst) - (\src) - 5
.endm

.macro memcall src, dst
    .section .patch,"d0" 
    .long (\src)
    .long 5
    .byte 0xE8
    .long (\dst) - (\src) - 5
.endm

.macro memcpy addr, inst
    .section .patch,"d0" 
    .long (\addr)
    .long (_memcpy_end_\@ - _memcpy_start_\@)
_memcpy_start_\@:
    \inst
_memcpy_end_\@:
.endm