82 lines
4.7 KiB
ArmAsm
82 lines
4.7 KiB
ArmAsm
/*
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Copyright Oliver Kowalke 2009.
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Distributed under the Boost Software License, Version 1.0.
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(See accompanying file LICENSE_1_0.txt or copy at
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http://www.boost.org/LICENSE_1_0.txt)
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*/
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/****************************************************************************************
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* *
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* ---------------------------------------------------------------------------------- *
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* | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | *
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* ---------------------------------------------------------------------------------- *
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* | 0x0 | 0x4 | 0x8 | 0xc | 0x10 | 0x14 | 0x18 | 0x1c | *
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* ---------------------------------------------------------------------------------- *
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* | RBX | R12 | R13 | R14 | *
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* ---------------------------------------------------------------------------------- *
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* ---------------------------------------------------------------------------------- *
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* | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | *
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* ---------------------------------------------------------------------------------- *
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* | 0x20 | 0x24 | 0x28 | 0x2c | 0x30 | 0x34 | 0x38 | 0x3c | *
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* ---------------------------------------------------------------------------------- *
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* | R15 | RBP | RSP | RIP | *
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* ---------------------------------------------------------------------------------- *
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* ---------------------------------------------------------------------------------- *
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* | 16 | 17 | 18 | 19 | | *
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* ---------------------------------------------------------------------------------- *
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* | 0x40 | 0x44 | 0x48 | 0x4c | | *
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* ---------------------------------------------------------------------------------- *
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* | sp | size | | *
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* ---------------------------------------------------------------------------------- *
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* ---------------------------------------------------------------------------------- *
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* | 20 | 21 | | *
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* ---------------------------------------------------------------------------------- *
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* | 0x50 | 0x54 | | *
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* ---------------------------------------------------------------------------------- *
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* | fc_mxcsr|fc_x87_cw| | *
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* ---------------------------------------------------------------------------------- *
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* *
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* **************************************************************************************/
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.text
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.globl make_fcontext
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#ifndef __APPLE__
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.type make_fcontext,@function
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#endif
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.align 8
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make_fcontext:
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leaq -0x58(%rdi), %rax /* reserve space for fcontext_t at top of context stack */
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/* shift address in RAX to lower 16 byte boundary */
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/* == pointer to fcontext_t and address of context stack */
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andq $-16, %rax
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movq %rdi, 0x40(%rax) /* save address of context stack pointer (base) in fcontext_t */
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movq %rsi, 0x48(%rax) /* save context stack size in fcontext_t */
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movq %rdx, 0x38(%rax) /* save address of context function in fcontext_t */
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stmxcsr 0x50(%rax) /* save MMX control and status word */
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fnstcw 0x54(%rax) /* save x87 control word */
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leaq -0x8(%rax), %rdx /* reserve space for the return address on context stack, (RSP - 0x8) % 16 == 0 */
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movq %rdx, 0x30(%rax) /* save address in RDX as stack pointer for context function */
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leaq finish(%rip), %rcx /* compute abs address of label finish */
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movq %rcx, (%rdx) /* save address of finish as return address for context function */
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/* entered after context function returns */
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ret /* return pointer to fcontext_t placed on context stack */
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finish:
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/* RSP points to same address as RSP on entry of context function + 0x8 */
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xorq %rdi, %rdi /* exit code is zero */
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call _exit@PLT /* exit application */
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hlt
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#ifndef __APPLE__
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.size make_fcontext,.-make_fcontext
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#endif
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