linux/arch/c6x/lib/divi.S

42 lines
1.2 KiB
ArmAsm

;; SPDX-License-Identifier: GPL-2.0-or-later
;; Copyright 2010 Free Software Foundation, Inc.
;; Contributed by Bernd Schmidt <bernds@codesourcery.com>.
;;
#include <linux/linkage.h>
;; ABI considerations for the divide functions
;; The following registers are call-used:
;; __c6xabi_divi A0,A1,A2,A4,A6,B0,B1,B2,B4,B5
;; __c6xabi_divu A0,A1,A2,A4,A6,B0,B1,B2,B4
;; __c6xabi_remi A1,A2,A4,A5,A6,B0,B1,B2,B4
;; __c6xabi_remu A1,A4,A5,A7,B0,B1,B2,B4
;;
;; In our implementation, divu and remu are leaf functions,
;; while both divi and remi call into divu.
;; A0 is not clobbered by any of the functions.
;; divu does not clobber B2 either, which is taken advantage of
;; in remi.
;; divi uses B5 to hold the original return address during
;; the call to divu.
;; remi uses B2 and A5 to hold the input values during the
;; call to divu. It stores B3 in on the stack.
.text
ENTRY(__c6xabi_divi)
call .s2 __c6xabi_divu
|| mv .d2 B3, B5
|| cmpgt .l1 0, A4, A1
|| cmpgt .l2 0, B4, B1
[A1] neg .l1 A4, A4
|| [B1] neg .l2 B4, B4
|| xor .s1x A1, B1, A1
[A1] addkpc .s2 _divu_ret, B3, 4
_divu_ret:
neg .l1 A4, A4
|| mv .l2 B3,B5
|| ret .s2 B5
nop 5
ENDPROC(__c6xabi_divi)