113 lines
2.4 KiB
Plaintext
113 lines
2.4 KiB
Plaintext
#
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mes 2,_EM_WSIZE,_EM_PSIZE
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;
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; layout of a setjmp buffer:
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;
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; -----------------
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; | flag | (!0 when blocked signals saved (POSIX))
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; -----------------
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; | signal mask/set | (for Berkeley 4.[2-] / POSIX)
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; -----------------
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; | |
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; | GTO descriptor |
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; | (SP, LB, PC) |
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; | |
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; -----------------
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;
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; setjmp saves the signalmask, PC, SP, and LB of caller, and creates a
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; GTO descriptor from this.
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; The big problem here is how to get the return address, i.e. the PC of
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; the caller; This problem is solved by the front-end, which must pass
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; it as an extra parameter to setjmp.
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; a GTO descriptor must be in the global data area
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gtobuf
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bss 3*_EM_PSIZE,0,0
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inp $fill_ret_area
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exp $__setjmp
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pro $__setjmp,0
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#if defined(_POSIX_SOURCE)
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; save mask of currently blocked signals.
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; longjmp must restore this mask
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lol _EM_PSIZE ; the flag integer at offset _EM_PSIZE
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lal 0
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loi _EM_PSIZE
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stf 3*_EM_PSIZE+_EM_LSIZE
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lol _EM_PSIZE ; the flag integer at offset _EM_PSIZE
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zeq *1
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lal 0
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loi _EM_PSIZE
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adp 3*_EM_PSIZE
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cal $__newsigset
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asp _EM_PSIZE
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1
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#elif defined(__BSD4_2)
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loc 0
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cal $sigblock
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asp _EM_WSIZE
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lfr _EM_WSIZE
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lal 0
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loi _EM_PSIZE
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stf 3*_EM_PSIZE
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#endif
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; create GTO descriptor for longjmp
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lxl 0
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dch ; Local Base of caller
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lxa 0 ; Stackpointer of caller
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lal _EM_PSIZE+_EM_WSIZE
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loi _EM_PSIZE ; Return address of caller
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lal 0
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loi _EM_PSIZE ; address of jmpbuf
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sti 3*_EM_PSIZE ; LB, SP, and PC stored in jmpbuf
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loc 0
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ret _EM_WSIZE ; setjmp must return 0
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end 0
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pro $fill_ret_area,0
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; put argument in function result area
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lol 0
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ret _EM_WSIZE
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end 0
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exp $longjmp
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pro $longjmp,?
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#if defined(_POSIX_SOURCE)
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; restore blocked mask
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lal 0
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loi _EM_PSIZE
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lof 3*_EM_PSIZE+_EM_LSIZE
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zeq *2
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lal 0
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loi _EM_PSIZE
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adp 3*_EM_PSIZE
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cal $__oldsigset
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asp _EM_PSIZE
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2
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#elif defined(__BSD4_2)
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; restore signal mask
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lal 0
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loi _EM_PSIZE
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lof 3*_EM_PSIZE
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cal $_sigsetmask
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asp _EM_WSIZE
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lfr _EM_WSIZE
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asp _EM_WSIZE
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#endif
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lal 0
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loi _EM_PSIZE ; address of jmpbuf
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lae gtobuf
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blm 3*_EM_PSIZE ; fill GTO descriptor from jmpbuf
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lol _EM_PSIZE ; second parameter of longjmp: the return value
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dup _EM_WSIZE
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zne *3
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; of course, longjmp may not return 0!
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inc
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3
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; put return value in function result area
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cal $fill_ret_area
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asp _EM_WSIZE
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gto gtobuf ; there we go ...
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; ASP and GTO do not damage function result area
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end 0
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