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https://sourceware.org/git/glibc.git
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367 lines
8.7 KiB
C
367 lines
8.7 KiB
C
/* Copyright (C) 2001-2024 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <errno.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <ucontext.h>
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#include <unistd.h>
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#include <link.h>
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#include <elf.h>
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#include <fpu_control.h>
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#include <sys/auxv.h>
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#include <support/support.h>
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#include <support/xstdio.h>
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static ucontext_t ctx[3];
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volatile int global;
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static int back_in_main;
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volatile static ElfW(auxv_t) *auxv = NULL;
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ElfW(Addr) query_auxv(int type)
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{
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FILE *auxv_f;
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ElfW(auxv_t) auxv_struct;
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ElfW(auxv_t) *auxv_temp;
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int i = 0;
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/* if the /proc/self/auxv file has not been manually copied into the heap
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yet, then do it */
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if(auxv == NULL)
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{
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auxv_f = fopen("/proc/self/auxv", "r");
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if(auxv_f == 0)
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{
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perror("Error opening file for reading");
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return 0;
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}
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auxv = xmalloc (getpagesize ());
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do
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{
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xfread (&auxv_struct, sizeof (ElfW(auxv_t)), 1, auxv_f);
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auxv[i] = auxv_struct;
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i++;
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} while(auxv_struct.a_type != AT_NULL);
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}
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auxv_temp = (ElfW(auxv_t) *)auxv;
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i = 0;
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do
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{
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if(auxv_temp[i].a_type == type)
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{
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return auxv_temp[i].a_un.a_val;
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}
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i++;
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} while (auxv_temp[i].a_type != AT_NULL);
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return 0;
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}
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typedef unsigned int di_fpscr_t __attribute__ ((__mode__ (__DI__)));
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typedef unsigned int si_fpscr_t __attribute__ ((__mode__ (__SI__)));
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#define _FPSCR_RESERVED 0xfffffff8ffffff04ULL
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#define _FPSCR_TEST0_DRN 0x0000000400000000ULL
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#define _FPSCR_TEST0_RN 0x0000000000000003ULL
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#define _FPSCR_TEST1_DRN 0x0000000300000000ULL
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#define _FPSCR_TEST1_RN 0x0000000000000002ULL
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/* Macros for accessing the hardware control word on Power6[x]. */
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#define _GET_DI_FPSCR(__fpscr) \
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({union { double d; di_fpscr_t fpscr; } u; \
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u.d = __builtin_mffs (); \
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(__fpscr) = u.fpscr; \
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u.fpscr; \
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})
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/* We make sure to zero fp after we use it in order to prevent stale data
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in an fp register from making a test-case pass erroneously. */
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# define _SET_DI_FPSCR(__fpscr) \
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{ union { double d; di_fpscr_t fpscr; } u; \
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register double fr; \
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u.fpscr = __fpscr; \
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fr = u.d; \
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/* Set the entire 64-bit FPSCR. */ \
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__asm__ (".machine push; " \
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".machine \"power6\"; " \
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"mtfsf 255,%0,1,0; " \
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".machine pop" : : "f" (fr)); \
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fr = 0.0; \
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}
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# define _GET_SI_FPSCR(__fpscr) \
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({union { double d; di_fpscr_t fpscr; } u; \
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u.d = __builtin_mffs (); \
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(__fpscr) = (si_fpscr_t) u.fpscr; \
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(si_fpscr_t) u.fpscr; \
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})
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/* We make sure to zero fp after we use it in order to prevent stale data
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in an fp register from making a test-case pass erroneously. */
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# define _SET_SI_FPSCR(__fpscr) \
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{ union { double d; di_fpscr_t fpscr; } u; \
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register double fr; \
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/* More-or-less arbitrary; this is a QNaN. */ \
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u.fpscr = 0xfff80000ULL << 32; \
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u.fpscr |= __fpscr & 0xffffffffULL; \
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fr = u.d; \
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__builtin_mtfsf (255, fr); \
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fr = 0.0; \
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}
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void prime_special_regs(int which)
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{
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ElfW(Addr) a_val;
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di_fpscr_t di_fpscr __attribute__ ((__aligned__(8)));
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a_val = query_auxv(AT_HWCAP);
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if(a_val == -1)
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{
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puts ("querying the auxv for the hwcap failed");
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_exit (1);
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}
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/* Indicates a 64-bit FPSCR. */
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if (a_val & PPC_FEATURE_HAS_DFP)
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{
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_GET_DI_FPSCR(di_fpscr);
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/* Overwrite the existing DRN and RN if there is one. */
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if (which == 0)
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di_fpscr = ((di_fpscr & _FPSCR_RESERVED) | (_FPSCR_TEST0_DRN | _FPSCR_TEST0_RN));
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else
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di_fpscr = ((di_fpscr & _FPSCR_RESERVED) | (_FPSCR_TEST1_DRN | _FPSCR_TEST1_RN));
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puts ("Priming 64-bit FPSCR with:");
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printf("0x%.16llx\n",(unsigned long long int)di_fpscr);
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_SET_DI_FPSCR(di_fpscr);
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}
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else
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{
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puts ("32-bit FPSCR found and will be tested.");
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_GET_SI_FPSCR(di_fpscr);
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/* Overwrite the existing RN if there is one. */
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if (which == 0)
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di_fpscr = ((di_fpscr & _FPSCR_RESERVED) | (_FPSCR_TEST0_RN));
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else
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di_fpscr = ((di_fpscr & _FPSCR_RESERVED) | (_FPSCR_TEST1_RN));
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puts ("Priming 32-bit FPSCR with:");
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printf("0x%.8lx\n",(unsigned long int) di_fpscr);
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_SET_SI_FPSCR(di_fpscr);
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}
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}
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void clear_special_regs(void)
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{
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ElfW(Addr) a_val;
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di_fpscr_t di_fpscr __attribute__ ((__aligned__(8)));
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union {
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double d;
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unsigned long long int lli;
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unsigned int li[2];
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} dlli;
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a_val = query_auxv(AT_HWCAP);
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if(a_val == -1)
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{
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puts ("querying the auxv for the hwcap failed");
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_exit (1);
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}
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#if __WORDSIZE == 32
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dlli.d = ctx[0].uc_mcontext.uc_regs->fpregs.fpscr;
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#else
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dlli.d = ctx[0].uc_mcontext.fp_regs[32];
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#endif
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puts("The FPSCR value saved in the ucontext_t is:");
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/* Indicates a 64-bit FPSCR. */
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if (a_val & PPC_FEATURE_HAS_DFP)
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{
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printf("0x%.16llx\n",dlli.lli);
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di_fpscr = 0x0;
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puts ("Clearing the 64-bit FPSCR to:");
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printf("0x%.16llx\n",(unsigned long long int) di_fpscr);
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_SET_DI_FPSCR(di_fpscr);
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}
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else
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{
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printf("0x%.8x\n",(unsigned int) dlli.li[1]);
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di_fpscr = 0x0;
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puts ("Clearing the 32-bit FPSCR to:");
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printf("0x%.8lx\n",(unsigned long int) di_fpscr);
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_SET_SI_FPSCR(di_fpscr);
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}
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}
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void test_special_regs(int which)
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{
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ElfW(Addr) a_val;
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unsigned long long int test;
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di_fpscr_t di_fpscr __attribute__ ((__aligned__(8)));
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a_val = query_auxv(AT_HWCAP);
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if(a_val == -1)
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{
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puts ("querying the auxv for the hwcap failed");
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_exit (2);
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}
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/* Indicates a 64-bit FPSCR. */
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if (a_val & PPC_FEATURE_HAS_DFP)
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{
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_GET_DI_FPSCR(di_fpscr);
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if (which == 0)
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puts ("After setcontext the 64-bit FPSCR contains:");
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else
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puts ("After swapcontext the 64-bit FPSCR contains:");
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printf("0x%.16llx\n",(unsigned long long int) di_fpscr);
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test = (_FPSCR_TEST0_DRN | _FPSCR_TEST0_RN);
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if((di_fpscr & (test)) != (test))
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{
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printf ("%s: DRN and RN bits set before getcontext were not preserved across [set|swap]context call: %m",__FUNCTION__);
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_exit (3);
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}
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}
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else
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{
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_GET_SI_FPSCR(di_fpscr);
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if (which == 0)
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puts ("After setcontext the 32-bit FPSCR contains:");
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else
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puts ("After swapcontext the 32-bit FPSCR contains:");
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printf("0x%.8lx\n",(unsigned long int) di_fpscr);
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test = _FPSCR_TEST0_RN;
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if((di_fpscr & test) != test)
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{
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printf ("%s: RN bit set before getcontext was not preserved across [set|swap]context call: %m",__FUNCTION__);
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_exit (4);
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}
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}
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}
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static void
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check_called (void)
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{
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if (back_in_main == 0)
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{
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puts ("program did not reach main again");
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_exit (5);
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}
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}
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int
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main (void)
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{
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atexit (check_called);
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puts ("priming the FPSCR with a marker");
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prime_special_regs (0);
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puts ("making contexts");
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if (getcontext (&ctx[0]) != 0)
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{
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if (errno == ENOSYS)
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{
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back_in_main = 1;
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exit (0);
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}
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printf ("%s: getcontext: %m\n", __FUNCTION__);
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exit (6);
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}
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/* Play some tricks with this context. */
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if (++global == 1)
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{
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clear_special_regs ( );
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if (setcontext (&ctx[0]) != 0)
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{
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printf ("%s: setcontext: %m\n", __FUNCTION__);
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exit (7);
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}
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}
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if (global != 2)
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{
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printf ("%s: 'global' not incremented twice\n", __FUNCTION__);
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exit (8);
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}
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test_special_regs (0);
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global = 0;
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if (getcontext (&ctx[0]) != 0)
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{
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printf ("%s: getcontext: %m\n", __FUNCTION__);
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exit (9);
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}
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if (++global == 1)
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{
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puts ("priming the FPSCR with a marker");
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prime_special_regs (1);
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puts ("swapping contexts");
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if (swapcontext (&ctx[1], &ctx[0]) != 0)
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{
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printf ("%s: swapcontext: %m\n", __FUNCTION__);
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exit (9);
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}
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}
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if (global != 2)
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{
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printf ("%s: 'global' not incremented twice\n", __FUNCTION__);
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exit (10);
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}
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test_special_regs (1);
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puts ("back at main program");
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back_in_main = 1;
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puts ("test succeeded");
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return 0;
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}
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