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; Copyright (C) 2011-2023 Free Software Foundation, Inc.
; Contributed by Red Hat.
;
; This file is free software; you can redistribute it and/or modify it
; under the terms of the GNU General Public License as published by the
; Free Software Foundation; either version 3, or (at your option) any
; later version.
;
; This file is distributed in the hope that it will be useful, but
; WITHOUT ANY WARRANTY; without even the implied warranty of
; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
; General Public License for more details.
;
; Under Section 7 of GPL version 3, you are granted additional
; permissions described in the GCC Runtime Library Exception, version
; 3.1, as published by the Free Software Foundation.
;
; You should have received a copy of the GNU General Public License and
; a copy of the GCC Runtime Library Exception along with this program;
; see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
; <http://www.gnu.org/licenses/>.
#include "vregs.h"
.text
;; int __cmpsi2 (signed long A, signed long B)
;;
;; Performs a signed comparison of A and B.
;; If A is less than B it returns 0. If A is greater
;; than B it returns 2. If they are equal it returns 1.
START_FUNC ___cmpsi2
;; A is at [sp+4]
;; B is at [sp+8]
;; Result put in R8
;; Initialise default return value.
onew bc
;; Compare the high words.
movw ax, [sp + 10]
movw de, ax
movw ax, [sp + 6]
cmpw ax, de
skz
br !!.Lconvert_to_signed
.Lcompare_bottom_words:
;; The top words are equal - compare the bottom words.
;; Note - code from __ucmpsi2 branches into here.
movw ax, [sp + 8]
movw de, ax
movw ax, [sp + 4]
cmpw ax, de
sknz
br !!.Lless_than_or_greater_than
;; The words are equal - return 1.
;; Note - we could branch to the return code at the end of the
;; function but a branch instruction takes 4 bytes, and the
;; return sequence itself is only 4 bytes long...
movw ax, bc
movw r8, ax
ret
.Lconvert_to_signed:
;; The top words are different. Unfortunately the comparison
;; is always unsigned, so to get a signed result we XOR the CY
;; flag with the top bits of AX and DE.
xor1 cy, a.7
mov a, d
xor1 cy, a.7
;; Fall through.
.Lless_than_or_greater_than:
;; We now have a signed less than/greater than result in CY.
;; Return 0 for less than, 2 for greater than.
;; Note - code from __ucmpsi2 branches into here.
incw bc
sknc
clrw bc
;; Get the result value, currently in BC, into r8
movw ax, bc
movw r8, ax
ret
END_FUNC ___cmpsi2
;; ------------------------------------------------------
;; int __ucmpsi2 (unsigned long A, unsigned long B)
;;
;; Performs an unsigned comparison of A and B.
;; If A is less than B it returns 0. If A is greater
;; than B it returns 2. If they are equal it returns 1.
START_FUNC ___ucmpsi2
;; A is at [sp+4]
;; B is at [sp+8]
;; Result put in R8..R9
;; Initialise default return value.
onew bc
;; Compare the high words.
movw ax, [sp + 10]
movw de, ax
movw ax, [sp + 6]
cmpw ax, de
skz
;; Note: These branches go into the __cmpsi2 code!
br !!.Lless_than_or_greater_than
br !!.Lcompare_bottom_words
END_FUNC ___ucmpsi2
;; ------------------------------------------------------
;; signed int __gcc_bcmp (const unsigned char *s1, const unsigned char *s2, size_t size)
;; Result is negative if S1 is less than S2,
;; positive if S1 is greater, 0 if S1 and S2 are equal.
START_FUNC __gcc_bcmp
;; S1 is at [sp+4]
;; S2 is at [sp+6]
;; SIZE is at [sp+8]
;; Result in r8/r9
movw r10, #0
1:
;; Compare R10 against the SIZE parameter
movw ax, [sp+8]
subw ax, r10
sknz
br !!1f
;; Load S2[r10] into R8
movw ax, [sp+6]
addw ax, r10
movw hl, ax
mov a, [hl]
mov r8, a
;; Load S1[r10] into A
movw ax, [sp+4]
addw ax, r10
movw hl, ax
mov a, [hl]
;; Increment offset
incw r10
;; Compare loaded bytes
cmp a, r8
sknz
br !!1b
;; They differ. Subtract *S2 from *S1 and return as the result.
mov x, a
mov a, #0
mov r9, #0
subw ax, r8
1:
movw r8, ax
ret
END_FUNC __gcc_bcmp
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