diff options
Diffstat (limited to 'libs/context/src/asm/fcontext_i386_sysv_macho_gas.S')
| -rw-r--r-- | libs/context/src/asm/fcontext_i386_sysv_macho_gas.S | 118 |
1 files changed, 118 insertions, 0 deletions
diff --git a/libs/context/src/asm/fcontext_i386_sysv_macho_gas.S b/libs/context/src/asm/fcontext_i386_sysv_macho_gas.S new file mode 100644 index 0000000000..a28c87576a --- /dev/null +++ b/libs/context/src/asm/fcontext_i386_sysv_macho_gas.S @@ -0,0 +1,118 @@ +/* + 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 | | * + * -------------------------------------------------------------- * + * | sbase | slimit | | * + * -------------------------------------------------------------- * + * -------------------------------------------------------------- * + * | 8 | 9 | | * + * -------------------------------------------------------------- * + * | 0x20 | 0x24 | | * + * -------------------------------------------------------------- * + * | fc_mxcsr|fc_x87_cw| | * + * -------------------------------------------------------------- * + * * + * *****************************************************************/ + +.text +.globl _jump_fcontext +.align 2 +_jump_fcontext: + movl 0x4(%esp), %ecx /* load address of the first fcontext_t arg */ + movl %edi, (%ecx) /* save EDI */ + movl %esi, 0x4(%ecx) /* save ESI */ + movl %ebx, 0x8(%ecx) /* save EBX */ + movl %ebp, 0xc(%ecx) /* save EBP */ + + leal 0x4(%esp), %eax /* exclude the return address */ + movl %eax, 0x10(%ecx) /* save as stack pointer */ + movl (%esp), %eax /* load return address */ + movl %eax, 0x14(%ecx) /* save return address */ + + movl 0x8(%esp), %edx /* load address of the second fcontext_t arg */ + movl (%edx), %edi /* restore EDI */ + movl 0x4(%edx), %esi /* restore ESI */ + movl 0x8(%edx), %ebx /* restore EBX */ + movl 0xc(%edx), %ebp /* restore EBP */ + + movl 0x10(%esp), %eax /* check if fpu enve preserving was requested */ + test %eax, %eax + je 1f + + stmxcsr 0x20(%ecx) /* save MMX control and status word */ + fnstcw 0x24(%ecx) /* save x87 control word */ + ldmxcsr 0x20(%edx) /* restore MMX control and status word */ + fldcw 0x24(%edx) /* restore x87 control word */ +1: + movl 0xc(%esp), %eax /* use third arg as return value after jump */ + + movl 0x10(%edx), %esp /* restore ESP */ + movl %eax, 0x4(%esp) /* use third arg as first arg in context function */ + movl 0x14(%edx), %edx /* fetch the address to return to */ + + jmp *%edx /* indirect jump to context */ + +.text +.globl _make_fcontext +.align 2 +_make_fcontext: + movl 0x4(%esp), %eax /* load address of the fcontext_t */ + movl %eax, (%eax) /* save the address of current context */ + movl 0x8(%esp), %ecx /* load the address of the context function */ + movl %ecx, 0x14(%eax) /* save the address of the context function */ + movl 0x18(%eax), %edx /* load the stack base */ + + pushl %eax /* save pointer to fcontext_t */ + pushl %ebx /* save EBX */ + pushl %edx /* stack pointer as arg for align_stack */ + call 1f +1: popl %ebx /* address of label 1 */ + addl $_GLOBAL_OFFSET_TABLE_+[.-1b], %ebx /* compute address of GOT and store it in EBX */ + call align_stack@PLT /* align stack */ + movl %eax, %edx /* begin of aligned stack */ + popl %eax /* remove arg for align_stack */ + popl %ebx /* restore EBX */ + popl %eax /* restore pointer to fcontext_t */ + + leal -0x14(%edx), %edx /* reserve space for the last frame on stack, (ESP + 4) % 16 == 0 */ + movl %edx, 0x10(%eax) /* save the aligned stack base */ + + stmxcsr 0x20(%eax) /* save MMX control and status word */ + fnstcw 0x24(%eax) /* save x87 control word */ + + call 2f +2: popl %ecx /* address of label 2 */ + addl $finish-2b, %ecx /* helper code executed after context function returns */ + movl %ecx, (%edx) + + xorl %eax, %eax + ret + +finish: + leal -0xc(%esp), %esp + + call 3f +3: popl %ebx /* address of label 3 */ + addl $_GLOBAL_OFFSET_TABLE_+[.-3b], %ebx /* compute address of GOT and store it in EBX */ + + xorl %eax, %eax + pushl %eax /* exit code is zero */ + call _exit@PLT /* exit application */ + hlt |