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/*
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 | 6 | 7 | *
* ---------------------------------------------------------------------------------- *
* | 0x0 | 0x4 | 0x8 | 0xc | 0x10 | 0x14 | 0x18 | 0x1c | *
* ---------------------------------------------------------------------------------- *
* | fc_mxcsr|fc_x87_cw| EDI | ESI | EBX | EBP | EIP | to | *
* ---------------------------------------------------------------------------------- *
* ---------------------------------------------------------------------------------- *
* | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | *
* ---------------------------------------------------------------------------------- *
* | 0x20 | | *
* ---------------------------------------------------------------------------------- *
* | data | | *
* ---------------------------------------------------------------------------------- *
* *
****************************************************************************************/
.text
.globl _make_fcontext
.align 2
_make_fcontext:
/* first arg of make_fcontext() == top of context-stack */
movl 0x4(%esp), %eax
/* reserve space for first argument of context-function
eax might already point to a 16byte border */
leal -0x8(%eax), %eax
/* shift address in EAX to lower 16 byte boundary */
andl $-16, %eax
/* reserve space for context-data on context-stack, and align the stack */
leal -0x34(%eax), %eax
/* third arg of make_fcontext() == address of context-function */
/* stored in EBX */
movl 0xc(%esp), %ecx
movl %ecx, 0x10(%eax)
/* save MMX control- and status-word */
stmxcsr (%eax)
/* save x87 control-word */
fnstcw 0x4(%eax)
/* compute abs address of label trampoline */
call 1f
/* address of trampoline 1 */
1: popl %ecx
/* compute abs address of label trampoline */
addl $trampoline-1b, %ecx
/* save address of trampoline as return address */
/* will be entered after calling jump_fcontext() first time */
movl %ecx, 0x18(%eax)
/* compute abs address of label finish */
call 2f
/* address of label 2 */
2: popl %ecx
/* compute abs address of label finish */
addl $finish-2b, %ecx
/* save address of finish as return-address for context-function */
/* will be entered after context-function returns */
movl %ecx, 0x14(%eax)
ret /* return pointer to context-data */
trampoline:
/* move transport_t for entering context-function */
movl %eax, (%esp)
movl %edx, 0x4(%esp)
pushl %ebp
/* jump to context-function */
jmp *%ebx
finish:
/* exit code is zero */
xorl %eax, %eax
movl %eax, (%esp)
/* exit application */
call __exit
hlt
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