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[/] [openrisc/] [trunk/] [gnu-dev/] [or1k-gcc/] [libgcc/] [config/] [rl78/] [cmpsi2.S] - Blame information for rev 734

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1 734 jeremybenn
;   Copyright (C) 2011 Free Software Foundation, Inc.
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;   Contributed by Red Hat.
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;
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; This file is free software; you can redistribute it and/or modify it
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; under the terms of the GNU General Public License as published by the
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; Free Software Foundation; either version 3, or (at your option) any
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; later version.
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;
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; This file is distributed in the hope that it will be useful, but
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; 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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; General Public License for more details.
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;
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; Under Section 7 of GPL version 3, you are granted additional
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; permissions described in the GCC Runtime Library Exception, version
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; 3.1, as published by the Free Software Foundation.
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;
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; You should have received a copy of the GNU General Public License and
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; a copy of the GCC Runtime Library Exception along with this program;
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; see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
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; .
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; clobberable
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r8      =       0xffef0
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        .text
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        ;;   int __cmpsi2 (signed long A, signed long B)
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        ;;
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        ;; Performs a signed comparison of A and B.
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        ;; If A is less than B it returns 0.  If A is greater
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        ;; than B it returns 2.  If they are equal it returns 1.
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        .global ___cmpsi2
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        .type   ___cmpsi2, @function
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___cmpsi2:
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        ;; A is at [sp+4]
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        ;; B is at [sp+8]
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        ;; Result put in R8
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        ;; Initialise default return value.
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        onew    bc
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        ;;  Compare the high words.
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        movw    ax, [sp + 10]
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        movw    de, ax
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        movw    ax, [sp + 6]
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        cmpw    ax, de
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        skz
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        br      !!.Lconvert_to_signed
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.Lcompare_bottom_words:
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        ;; The top words are equal - compare the bottom words.
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        ;; Note - code from __ucmpsi2 branches into here.
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        movw   ax, [sp + 8]
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        movw   de, ax
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        movw   ax, [sp + 4]
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        cmpw   ax, de
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        sknz
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        br      !!.Lless_than_or_greater_than
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        ;; The words are equal - return 1.
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        ;; Note - we could branch to the return code at the end of the
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        ;; function but a branch instruction takes 4 bytes, and the
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        ;; return sequence itself is only 4 bytes long...
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        movw    ax, bc
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        movw    r8, ax
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        ret
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.Lconvert_to_signed:
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        ;; The top words are different.  Unfortunately the comparison
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        ;; is always unsigned, so to get a signed result we XOR the CY
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        ;; flag with the top bits of AX and DE.
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        xor1    cy, a.7
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        mov     a, d
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        xor1    cy, a.7
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        ;; Fall through.
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.Lless_than_or_greater_than:
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        ;; We now have a signed less than/greater than result in CY.
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        ;; Return 0 for less than, 2 for greater than.
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        ;; Note - code from __ucmpsi2 branches into here.
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        incw    bc
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        sknc
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        clrw    bc
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        ;; Get the result value, currently in BC, into r8
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        movw    ax, bc
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        movw    r8, ax
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        ret
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        .size   ___cmpsi2, . - ___cmpsi2
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        ;;   int __ucmpsi2 (unsigned long A, unsigned long B)
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        ;;
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        ;; Performs an unsigned comparison of A and B.
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        ;; If A is less than B it returns 0.  If A is greater
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        ;; than B it returns 2.  If they are equal it returns 1.
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        .global ___ucmpsi2
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        .type   ___ucmpsi2, @function
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___ucmpsi2:
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        ;; A is at [sp+4]
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        ;; B is at [sp+8]
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        ;; Result put in R8..R9
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        ;; Initialise default return value.
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        onew    bc
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        ;;  Compare the high words.
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        movw    ax, [sp + 10]
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        movw    de, ax
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        movw    ax, [sp + 6]
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        cmpw    ax, de
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        skz
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        ;; Note: These branches go into the __cmpsi2 code!
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        br      !!.Lless_than_or_greater_than
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        br      !!.Lcompare_bottom_words
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        .size   ___ucmpsi2, . - ___ucmpsi2
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