;; 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_divu)
  	;; We use a series of up to 31 subc instructions.  First, we find
  	;; out how many leading zero bits there are in the divisor.  This
  	;; gives us both a shift count for aligning (shifting) the divisor
  	;; to the, and the number of times we have to execute subc.
  
  	;; At the end, we have both the remainder and most of the quotient
  	;; in A4.  The top bit of the quotient is computed first and is
  	;; placed in A2.
  
  	;; Return immediately if the dividend is zero.
  	 mv	.s2x	A4, B1
     [B1]	 lmbd	.l2	1, B4, B1
  || [!B1] b	.s2	B3	; RETURN A
  || [!B1] mvk	.d2	1, B4
  	 mv	.l1x	B1, A6
  ||	 shl	.s2	B4, B1, B4
  
  	;; The loop performs a maximum of 28 steps, so we do the
  	;; first 3 here.
  	 cmpltu	.l1x	A4, B4, A2
     [!A2] sub	.l1x	A4, B4, A4
  ||	 shru	.s2	B4, 1, B4
  ||	 xor	.s1	1, A2, A2
  
  	 shl	.s1	A2, 31, A2
  || [B1]	 subc	.l1x	A4,B4,A4
  || [B1]	 add	.s2	-1, B1, B1
     [B1]	 subc	.l1x	A4,B4,A4
  || [B1]	 add	.s2	-1, B1, B1
  
  	;; RETURN A may happen here (note: must happen before the next branch)
  _divu_loop:
  	 cmpgt	.l2	B1, 7, B0
  || [B1]	 subc	.l1x	A4,B4,A4
  || [B1]	 add	.s2	-1, B1, B1
     [B1]	 subc	.l1x	A4,B4,A4
  || [B1]	 add	.s2	-1, B1, B1
  || [B0]  b	.s1	_divu_loop
     [B1]	 subc	.l1x	A4,B4,A4
  || [B1]	 add	.s2	-1, B1, B1
     [B1]	 subc	.l1x	A4,B4,A4
  || [B1]	 add	.s2	-1, B1, B1
     [B1]	 subc	.l1x	A4,B4,A4
  || [B1]	 add	.s2	-1, B1, B1
     [B1]	 subc	.l1x	A4,B4,A4
  || [B1]	 add	.s2	-1, B1, B1
     [B1]	 subc	.l1x	A4,B4,A4
  || [B1]	 add	.s2	-1, B1, B1
  	;; loop backwards branch happens here
  
  	 ret	.s2	B3
  ||	 mvk	.s1	32, A1
  	 sub	.l1	A1, A6, A6
  	 shl	.s1	A4, A6, A4
  	 shru	.s1	A4, 1, A4
  ||	 sub	.l1	A6, 1, A6
  	 or	.l1	A2, A4, A4
  	 shru	.s1	A4, A6, A4
  	 nop
  ENDPROC(__c6xabi_divu)