/*
Copyright Oliver Kowalke 2009.
Distributed under the Boost Software License, Version 1.0.
(See accompanying file LICENSE_1_0.txt or copy at
http://www.boost.org/LICENSE_1_0.txt)
*/
/********************************************************************
* *
* -------------------------------------------------------------- *
* | 0 | 1 | 2 | 3 | 4 | 5 | *
* -------------------------------------------------------------- *
* | 0x0 | 0x4 | 0x8 | 0xc | 0x10 | 0x14 | *
* -------------------------------------------------------------- *
* | EDI | ESI | EBX | EBP | ESP | EIP | *
* -------------------------------------------------------------- *
* -------------------------------------------------------------- *
* | 6 | 7 | | *
* -------------------------------------------------------------- *
* | 0x18 | 0x1c | | *
* -------------------------------------------------------------- *
* | sp | size | | *
* -------------------------------------------------------------- *
* -------------------------------------------------------------- *
* | 8 | 9 | | *
* -------------------------------------------------------------- *
* | 0x20 | 0x24 | | *
* -------------------------------------------------------------- *
* | fc_mxcsr|fc_x87_cw| | *
* -------------------------------------------------------------- *
* *
* *****************************************************************/
.text
.globl make_fcontext
.align 2
.type make_fcontext,@function
make_fcontext:
movl 0x4(%esp), %eax /* load 1. arg of make_fcontext, pointer to context stack (base) */
leal -0x28(%eax), %eax /* reserve space for fcontext_t at top of context stack */
/* shift address in EAX to lower 16 byte boundary */
/* == pointer to fcontext_t and address of context stack */
andl $-16, %eax
movl 0x4(%esp), %edx /* load 1. arg of make_fcontext, pointer to context stack (base) */
movl %edx, 0x18(%eax) /* save address of context stack (base) in fcontext_t */
movl 0x8(%esp), %edx /* load 2. arg of make_fcontext, context stack size */
movl %edx, 0x1c(%eax) /* save stack size in fcontext_t */
movl 0xc(%esp), %edx /* load 3. arg of make_fcontext, pointer to context function */
movl %edx, 0x14(%eax) /* save address of context function in fcontext_t */
stmxcsr 0x20(%eax) /* save MMX control and status word */
fnstcw 0x24(%eax) /* save x87 control word */
leal -0x14(%eax), %edx /* reserve space for the last frame on context stack; (ESP - 0x4) % 16 == 0 */
movl %edx, 0x10(%eax) /* save address in EDX as stack pointer for context function */
call 1f
1: popl %ecx /* address of label 2 */
addl $finish-1b, %ecx /* compute abs address of label finish */
movl %ecx, (%edx) /* save address of finish as return address for context functions */
/* entered after context function returns */
ret
finish:
/* ESP points to same address as ESP on entry of context function + 0x4 */
call 2f
2: popl %ebx /* address of label 3 */
addl $_GLOBAL_OFFSET_TABLE_+[.-2b], %ebx /* compute address of GOT and store it in EBX */
xorl %eax, %eax
movl %eax, (%esp) /* exit code is zero */
call _exit@PLT /* exit application */
hlt
.size make_fcontext,.-make_fcontext
/* Mark that we don't need executable stack. */
.section .note.GNU-stack,"",%progbits
Add the following code to your website.
For more information on customizing the embed code, read Embedding Snippets.