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zsvjmp.s
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zsvjmp.s
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.file "zsvjmp.s"
# ZSVJMP, ZDOJMP -- Set up a jump (non-local goto) by saving the processor
# registers in the buffer jmpbuf. A subsequent call to ZDOJMP restores
# the registers, effecting a call in the context of the procedure which
# originally called ZSVJMP, but with the new status code. These are Fortran
# callable procedures.
#
# zsvjmp (jmp_buf, status) # (returns status)
# zdojmp (jmp_buf, status) # (passes status to zsvjmp)
#
# These routines are directly comparable to the UNIX setjmp/longjmp, except
# that they are Fortran callable kernel routines, i.e., trailing underscore,
# call by reference, and no function returns. ZSVJMP requires an assembler
# jacket routine to avoid modifying the call stack, but relies upon setjmp
# to do the real work. ZDOJMP is implemented as a portable C routine in OS,
# calling longjmp to do the restore. In these routines, JMP_BUF consists
# of one longword containing the address of the STATUS variable, followed
# by the "jmp_buf" used by setjmp/longjmp.
#
# This file contains the FreeBSD (x86) version of ZSVJMP.
# Modified to remove leading underscore for ELF (Jan99).
#.globl _zsvjmp_
.globl zsvjmp_
# The following has nothing to do with ZSVJMP, and is included here
# only because this assembler module is loaded with every process.
# This code sets the value of the symbol MEM (the VOS or Fortran Mem
# common) to zero, setting the origin for IRAF pointers to zero
# rather than some arbitrary value, and ensuring that the MEM common
# is aligned for all datatypes as well as page aligned. A further
# advantage is that references to NULL pointers are likely to cause a
# memory violation.
#.globl mem_
#mem_ = 0
.globl _mem_
_mem_ = 0
zsvjmp_:
# %rsi ... &status %rdi ... &jumpbuf
movq %rsi, (%rdi) # store &status in jmpbuf[0]
movl $0, (%rsi) # zero the value of status
addq $8, %rdi # change point to &jmpbuf[1]
movl $0, %esi # change arg2 to zero
jmp __sigsetjmp # let sigsetjmp do the rest