1 ;; SPDX-License-Identifier: GPL-2.0-or-later 2 ;; Copyright 2010 Free Software Foundation, Inc. 3 ;; Contributed by Bernd Schmidt <bernds@codesourcery.com>. 4 ;; 5 6 #include <linux/linkage.h> 7 8 ;; ABI considerations for the divide functions 9 ;; The following registers are call-used: 10 ;; __c6xabi_divi A0,A1,A2,A4,A6,B0,B1,B2,B4,B5 11 ;; __c6xabi_divu A0,A1,A2,A4,A6,B0,B1,B2,B4 12 ;; __c6xabi_remi A1,A2,A4,A5,A6,B0,B1,B2,B4 13 ;; __c6xabi_remu A1,A4,A5,A7,B0,B1,B2,B4 14 ;; 15 ;; In our implementation, divu and remu are leaf functions, 16 ;; while both divi and remi call into divu. 17 ;; A0 is not clobbered by any of the functions. 18 ;; divu does not clobber B2 either, which is taken advantage of 19 ;; in remi. 20 ;; divi uses B5 to hold the original return address during 21 ;; the call to divu. 22 ;; remi uses B2 and A5 to hold the input values during the 23 ;; call to divu. It stores B3 in on the stack. 24 25 .text 26 27 ENTRY(__c6xabi_remi) 28 stw .d2t2 B3, *B15--[2] 29 || cmpgt .l1 0, A4, A1 30 || cmpgt .l2 0, B4, B2 31 || mv .s1 A4, A5 32 || call .s2 __c6xabi_divu 33 34 [A1] neg .l1 A4, A4 35 || [B2] neg .l2 B4, B4 36 || xor .s2x B2, A1, B0 37 || mv .d2 B4, B2 38 39 [B0] addkpc .s2 _divu_ret_1, B3, 1 40 [!B0] addkpc .s2 _divu_ret_2, B3, 1 41 nop 2 42 _divu_ret_1: 43 neg .l1 A4, A4 44 _divu_ret_2: 45 ldw .d2t2 *++B15[2], B3 46 47 mpy32 .m1x A4, B2, A6 48 nop 3 49 ret .s2 B3 50 sub .l1 A5, A6, A4 51 nop 4 52 ENDPROC(__c6xabi_remi) 53