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glibc  2.9
__longjmp.c
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00001 /* Copyright (C) 1992, 1995, 1997, 2000 Free Software Foundation, Inc.
00002    This file is part of the GNU C Library.
00003    Contributed by Brendan Kehoe (brendan@zen.org).
00004 
00005    The GNU C Library is free software; you can redistribute it and/or
00006    modify it under the terms of the GNU Lesser General Public
00007    License as published by the Free Software Foundation; either
00008    version 2.1 of the License, or (at your option) any later version.
00009 
00010    The GNU C Library is distributed in the hope that it will be useful,
00011    but WITHOUT ANY WARRANTY; without even the implied warranty of
00012    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00013    Lesser General Public License for more details.
00014 
00015    You should have received a copy of the GNU Lesser General Public
00016    License along with the GNU C Library; if not, write to the Free
00017    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
00018    02111-1307 USA.  */
00019 
00020 #include <setjmp.h>
00021 #include <stdlib.h>
00022 
00023 #undef __longjmp
00024 
00025 #ifndef       __GNUC__
00026   #error This file uses GNU C extensions; you must compile with GCC.
00027 #endif
00028 
00029 void
00030 __longjmp (env, val_arg)
00031      __jmp_buf env;
00032      int val_arg;
00033 {
00034   /* gcc 1.39.19 miscompiled the longjmp routine (as it did setjmp before
00035      the hack around it); force it to use $a1 for the longjmp value.
00036      Without this it saves $a1 in a register which gets clobbered
00037      along the way.  */
00038   register int val asm ("a1");
00039 
00040 #ifdef __mips_hard_float
00041   /* Pull back the floating point callee-saved registers.  */
00042   asm volatile ("l.d $f20, %0" : : "m" (env[0].__fpregs[0]));
00043   asm volatile ("l.d $f22, %0" : : "m" (env[0].__fpregs[1]));
00044   asm volatile ("l.d $f24, %0" : : "m" (env[0].__fpregs[2]));
00045   asm volatile ("l.d $f26, %0" : : "m" (env[0].__fpregs[3]));
00046   asm volatile ("l.d $f28, %0" : : "m" (env[0].__fpregs[4]));
00047   asm volatile ("l.d $f30, %0" : : "m" (env[0].__fpregs[5]));
00048 
00049   /* Get and reconstruct the floating point csr.  */
00050   asm volatile ("lw $2, %0" : : "m" (env[0].__fpc_csr));
00051   asm volatile ("ctc1 $2, $31");
00052 #endif
00053 
00054   /* Get the GP. */
00055   asm volatile ("lw $gp, %0" : : "m" (env[0].__gp));
00056 
00057   /* Get the callee-saved registers.  */
00058   asm volatile ("lw $16, %0" : : "m" (env[0].__regs[0]));
00059   asm volatile ("lw $17, %0" : : "m" (env[0].__regs[1]));
00060   asm volatile ("lw $18, %0" : : "m" (env[0].__regs[2]));
00061   asm volatile ("lw $19, %0" : : "m" (env[0].__regs[3]));
00062   asm volatile ("lw $20, %0" : : "m" (env[0].__regs[4]));
00063   asm volatile ("lw $21, %0" : : "m" (env[0].__regs[5]));
00064   asm volatile ("lw $22, %0" : : "m" (env[0].__regs[6]));
00065   asm volatile ("lw $23, %0" : : "m" (env[0].__regs[7]));
00066 
00067   /* Get the PC.  */
00068   asm volatile ("lw $25, %0" : : "m" (env[0].__pc));
00069 
00070   /* Restore the stack pointer and the FP.  They have to be restored
00071      last and in a single asm as gcc, depending on options used, may
00072      use either of them to access env.  */
00073   asm volatile ("lw $29, %0\n\t"
00074               "lw $30, %1\n\t" : : "m" (env[0].__sp), "m" (env[0].__fp));
00075 
00076 /* Give setjmp 1 if given a 0, or what they gave us if non-zero.  */
00077   if (val == 0)
00078     asm volatile ("li $2, 1");
00079   else
00080     asm volatile ("move $2, %0" : : "r" (val));
00081 
00082   asm volatile ("jr $25");
00083 
00084   /* Avoid `volatile function does return' warnings.  */
00085   for (;;);
00086 }