53 lines
1.3 KiB
ArmAsm
53 lines
1.3 KiB
ArmAsm
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;; SPDX-License-Identifier: GPL-2.0-or-later
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;; Copyright 2010 Free Software Foundation, Inc.
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;; Contributed by Bernd Schmidt <bernds@codesourcery.com>.
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;;
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#include <linux/linkage.h>
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;; ABI considerations for the divide functions
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;; The following registers are call-used:
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;; __c6xabi_divi A0,A1,A2,A4,A6,B0,B1,B2,B4,B5
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;; __c6xabi_divu A0,A1,A2,A4,A6,B0,B1,B2,B4
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;; __c6xabi_remi A1,A2,A4,A5,A6,B0,B1,B2,B4
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;; __c6xabi_remu A1,A4,A5,A7,B0,B1,B2,B4
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;;
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;; In our implementation, divu and remu are leaf functions,
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;; while both divi and remi call into divu.
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;; A0 is not clobbered by any of the functions.
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;; divu does not clobber B2 either, which is taken advantage of
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;; in remi.
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;; divi uses B5 to hold the original return address during
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;; the call to divu.
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;; remi uses B2 and A5 to hold the input values during the
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;; call to divu. It stores B3 in on the stack.
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.text
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ENTRY(__c6xabi_remi)
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stw .d2t2 B3, *B15--[2]
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|| cmpgt .l1 0, A4, A1
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|| cmpgt .l2 0, B4, B2
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|| mv .s1 A4, A5
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|| call .s2 __c6xabi_divu
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[A1] neg .l1 A4, A4
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|| [B2] neg .l2 B4, B4
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|| xor .s2x B2, A1, B0
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|| mv .d2 B4, B2
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[B0] addkpc .s2 _divu_ret_1, B3, 1
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[!B0] addkpc .s2 _divu_ret_2, B3, 1
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nop 2
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_divu_ret_1:
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neg .l1 A4, A4
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_divu_ret_2:
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ldw .d2t2 *++B15[2], B3
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mpy32 .m1x A4, B2, A6
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nop 3
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ret .s2 B3
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sub .l1 A5, A6, A4
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nop 4
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ENDPROC(__c6xabi_remi)
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