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[/] [openrisc/] [trunk/] [gnu-src/] [newlib-1.18.0/] [newlib/] [libc/] [machine/] [xscale/] [setjmp.S] - Blame information for rev 207

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1 207 jeremybenn
/* This is a simple version of setjmp and longjmp.
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   Nick Clifton, Cygnus Solutions, 13 June 1997.  */
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/* ANSI concatenation macros.  */
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#define CONCAT(a, b)  CONCAT2(a, b)
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#define CONCAT2(a, b) a##b
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#ifndef __USER_LABEL_PREFIX__
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#error  __USER_LABEL_PREFIX__ not defined
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#endif
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#define SYM(x) CONCAT (__USER_LABEL_PREFIX__, x)
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#ifdef __ELF__
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#define TYPE(x) .type SYM(x),function
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#define SIZE(x) .size SYM(x), . - SYM(x)
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#else
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#define TYPE(x)
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#define SIZE(x)
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#endif
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/* Arm/Thumb interworking support:
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   The interworking scheme expects functions to use a BX instruction
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   to return control to their parent.  Since we need this code to work
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   in both interworked and non-interworked environments as well as with
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   older processors which do not have the BX instruction we do the
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   following:
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        Test the return address.
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        If the bottom bit is clear perform an "old style" function exit.
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        (We know that we are in ARM mode and returning to an ARM mode caller).
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        Otherwise use the BX instruction to perform the function exit.
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   We know that we will never attempt to perform the BX instruction on
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   an older processor, because that kind of processor will never be
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   interworked, and a return address with the bottom bit set will never
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   be generated.
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   In addition, we do not actually assemble the BX instruction as this would
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   require us to tell the assembler that the processor is an ARM7TDMI and
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   it would store this information in the binary.  We want this binary to be
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   able to be linked with binaries compiled for older processors however, so
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   we do not want such information stored there.
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   If we are running using the APCS-26 convention however, then we never
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   test the bottom bit, because this is part of the processor status.
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   Instead we just do a normal return, since we know that we cannot be
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   returning to a Thumb caller - the Thumb does not support APCS-26.
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   Function entry is much simpler.  If we are compiling for the Thumb we
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   just switch into ARM mode and then drop through into the rest of the
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   function.  The function exit code will take care of the restore to
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   Thumb mode.  */
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#ifdef __APCS_26__
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#define RET     movs            pc, lr
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#else
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#define RET     tst             lr, #1; \
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                moveq           pc, lr ; \
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.word           0xe12fff1e      /* bx lr */
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#endif
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#ifdef __thumb__
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#define MODE            .thumb_func
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.macro PROLOGUE name
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        .code 16
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        bx      pc
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        nop
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        .code 32
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SYM (.arm_start_of.\name):
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.endm
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#else
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#define MODE            .code 32
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.macro PROLOGUE name
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.endm
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#endif
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.macro FUNC_START name
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        .text
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        .align 2
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        MODE
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        .globl SYM (\name)
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        TYPE (\name)
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SYM (\name):
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        PROLOGUE \name
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.endm
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.macro FUNC_END name
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        RET
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        SIZE (\name)
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.endm
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/* --------------------------------------------------------------------
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                 int setjmp (jmp_buf);
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   -------------------------------------------------------------------- */
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        FUNC_START setjmp
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        /* Save all the callee-preserved registers into the jump buffer.  */
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        stmea           a1!, { v1-v7, fp, ip, sp, lr }
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#if 0   /* Simulator does not cope with FP instructions yet.  */
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#ifndef __SOFTFP__
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        /* Save the floating point registers.  */
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        sfmea           f4, 4, [a1]
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#endif
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#endif
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        /* When setting up the jump buffer return 0.  */
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        mov             a1, #0
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        FUNC_END setjmp
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/* --------------------------------------------------------------------
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                volatile void longjmp (jmp_buf, int);
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   -------------------------------------------------------------------- */
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        FUNC_START longjmp
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        /* If we have stack extension code it ought to be handled here.  */
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        /* Restore the registers, retrieving the state when setjmp() was called.  */
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        ldmfd           a1!, { v1-v7, fp, ip, sp, lr }
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#if 0   /* Simulator does not cope with FP instructions yet.  */
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#ifndef __SOFTFP__
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        /* Restore floating point registers as well.  */
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        lfmfd           f4, 4, [a1]
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#endif
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#endif
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        /* Put the return value into the integer result register.
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           But if it is zero then return 1 instead.  */
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        movs            a1, a2
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        moveq           a1, #1
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        FUNC_END longjmp
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