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