88 lines
2.7 KiB
C
88 lines
2.7 KiB
C
/*
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* this is the internal transfer function.
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*
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* HISTORY
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* 25-Jan-12 Alexey Borzenkov <snaury@gmail.com>
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* Fixed Linux/S390 port to work correctly with
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* different optimization options both on 31-bit
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* and 64-bit. Thanks to Stefan Raabe for lots
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* of testing.
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* 24-Nov-02 Christian Tismer <tismer@tismer.com>
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* needed to add another magic constant to insure
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* that f in slp_eval_frame(PyFrameObject *f)
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* STACK_REFPLUS will probably be 1 in most cases.
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* gets included into the saved stack area.
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* 06-Oct-02 Gustavo Niemeyer <niemeyer@conectiva.com>
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* Ported to Linux/S390.
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*/
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#define STACK_REFPLUS 1
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#ifdef SLP_EVAL
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#ifdef __s390x__
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#define STACK_MAGIC 20 /* 20 * 8 = 160 bytes of function call area */
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#else
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#define STACK_MAGIC 24 /* 24 * 4 = 96 bytes of function call area */
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#endif
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/* Technically, r11-r13 also need saving, but function prolog starts
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with stm(g) and since there are so many saved registers already
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it won't be optimized, resulting in all r6-r15 being saved */
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#define REGS_TO_SAVE "r6", "r7", "r8", "r9", "r10", "r14", \
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"f0", "f1", "f2", "f3", "f4", "f5", "f6", "f7", \
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"f8", "f9", "f10", "f11", "f12", "f13", "f14", "f15"
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static int
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slp_switch(void)
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{
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register int ret;
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register long *stackref, stsizediff;
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__asm__ volatile ("" : : : REGS_TO_SAVE);
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#ifdef __s390x__
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__asm__ volatile ("lgr %0, 15" : "=r" (stackref) : );
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#else
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__asm__ volatile ("lr %0, 15" : "=r" (stackref) : );
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#endif
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{
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SLP_SAVE_STATE(stackref, stsizediff);
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/* N.B.
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r11 may be used as the frame pointer, and in that case it cannot be
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clobbered and needs offsetting just like the stack pointer (but in cases
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where frame pointer isn't used we might clobber it accidentally). What's
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scary is that r11 is 2nd (and even 1st when GOT is used) callee saved
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register that gcc would chose for surviving function calls. However,
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since r6-r10 are clobbered above, their cost for reuse is reduced, so
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gcc IRA will chose them over r11 (not seeing r11 is implicitly saved),
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making it relatively safe to offset in all cases. :) */
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__asm__ volatile (
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#ifdef __s390x__
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"agr 15, %0\n\t"
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"agr 11, %0"
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#else
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"ar 15, %0\n\t"
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"ar 11, %0"
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#endif
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: /* no outputs */
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: "r" (stsizediff)
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);
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SLP_RESTORE_STATE();
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}
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__asm__ volatile ("" : : : REGS_TO_SAVE);
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__asm__ volatile ("lhi %0, 0" : "=r" (ret) : );
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return ret;
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}
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#endif
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/*
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* further self-processing support
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*/
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/*
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* if you want to add self-inspection tools, place them
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* here. See the x86_msvc for the necessary defines.
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* These features are highly experimental und not
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* essential yet.
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*/
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