50 lines
1.5 KiB
ArmAsm
50 lines
1.5 KiB
ArmAsm
;; Copyright (C) 2010 Texas Instruments Incorporated
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;; Contributed by Mark Salter <msalter@redhat.com>.
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;;
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;; This program is free software; you can redistribute it and/or modify
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;; it under the terms of the GNU General Public License as published by
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;; the Free Software Foundation; either version 2 of the License, or
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;; (at your option) any later version.
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;;
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;; This program is distributed in the hope that it will be useful,
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;; but WITHOUT ANY WARRANTY; without even the implied warranty of
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;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;; GNU General Public License for more details.
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;;
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;; You should have received a copy of the GNU General Public License
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;; along with this program; if not, write to the Free Software
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;; Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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#include <linux/linkage.h>
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;; uint64_t __c6xabi_mpyll(uint64_t x, uint64_t y)
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;;
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;; 64x64 multiply
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;; First compute partial results using 32-bit parts of x and y:
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;;
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;; b63 b32 b31 b0
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;; -----------------------------
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;; | 1 | 0 |
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;; -----------------------------
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;;
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;; P0 = X0*Y0
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;; P1 = X0*Y1 + X1*Y0
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;; P2 = X1*Y1
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;;
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;; result = (P2 << 64) + (P1 << 32) + P0
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;;
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;; Since the result is also 64-bit, we can skip the P2 term.
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.text
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ENTRY(__c6xabi_mpyll)
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mpy32u .m1x A4,B4,A1:A0 ; X0*Y0
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b .s2 B3
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|| mpy32u .m2x B5,A4,B1:B0 ; X0*Y1 (don't need upper 32-bits)
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|| mpy32u .m1x A5,B4,A3:A2 ; X1*Y0 (don't need upper 32-bits)
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nop
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nop
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mv .s1 A0,A4
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add .l1x A2,B0,A5
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add .s1 A1,A5,A5
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ENDPROC(__c6xabi_mpyll)
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