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.section .data
.globl caller_return
caller_return:
.long 0
.globl report_entry
report_entry:
.long null_call
.globl report_ret
report_ret:
.long null_call
.global wrapper_target
wrapper_target:
.long null_call
.section .text
.globl null_call
.type null_call, @function
.balign 16,0x90
null_call:
ret
.globl wrapper
.type wrapper, @function
.balign 16,0x90
wrapper:
pusha # store registers (EAX, ECX, EDX, EBX, ESP, EBP, ESI, EDI)
pushf # store flags
push %ebp # set up a stack frame
movl %esp, %ebp
leal 4(%ebp), %eax # push flags addr
push %eax
leal 8(%ebp), %eax # push registers addr
push %eax
leal 40(%ebp), %edx
movl (%ebp), %eax
subl %edx, %eax
push %eax
push %edx
call *report_entry # report entry
test %eax, %eax
jnz .Ldone
leave # restore %esp, %ebp
popf # restore flags
popa # restore registers
popl caller_return # switch return addresses
pushl $.Lwrapper_return
jmp *wrapper_target # wrapper_target should return at .Lwrapper_return
.balign 16, 0x90
.Lwrapper_return:
pushl caller_return # restore the original return address
pusha # more for reference sake here
pushf
push %ebp # set up a stack frame
movl %esp, %ebp
leal 4(%ebp), %eax # push flags addr
push %eax
leal 8(%ebp), %eax # push registers addr
push %eax
leal 40(%ebp), %edx # push stack top address (relative to our entry)
movl (%ebp), %eax
subl %edx, %eax # calculate difference between entry and previous frame
push %eax
push %edx
call *report_ret # report the return information (same args)
.Ldone:
leave
popf
popa
ret
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