kernel / pub / scm / linux / kernel / git / joro / linux / e5d081f4686f9c6be8ab3d34dfcdb0afdbbdeefd / . / arch / c6x / lib / mpyll.S

;; Copyright (C) 2010 Texas Instruments Incorporated | |

;; Contributed by Mark Salter <msalter@redhat.com>. | |

;; | |

;; This program is free software; you can redistribute it and/or modify | |

;; it under the terms of the GNU General Public License as published by | |

;; the Free Software Foundation; either version 2 of the License, or | |

;; (at your option) any later version. | |

;; | |

;; This program is distributed in the hope that it will be useful, | |

;; but WITHOUT ANY WARRANTY; without even the implied warranty of | |

;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |

;; GNU General Public License for more details. | |

;; | |

;; You should have received a copy of the GNU General Public License | |

;; along with this program; if not, write to the Free Software | |

;; Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. | |

#include <linux/linkage.h> | |

;; uint64_t __c6xabi_mpyll(uint64_t x, uint64_t y) | |

;; | |

;; 64x64 multiply | |

;; First compute partial results using 32-bit parts of x and y: | |

;; | |

;; b63 b32 b31 b0 | |

;; ----------------------------- | |

;; | 1 | 0 | | |

;; ----------------------------- | |

;; | |

;; P0 = X0*Y0 | |

;; P1 = X0*Y1 + X1*Y0 | |

;; P2 = X1*Y1 | |

;; | |

;; result = (P2 << 64) + (P1 << 32) + P0 | |

;; | |

;; Since the result is also 64-bit, we can skip the P2 term. | |

.text | |

ENTRY(__c6xabi_mpyll) | |

mpy32u .m1x A4,B4,A1:A0 ; X0*Y0 | |

b .s2 B3 | |

|| mpy32u .m2x B5,A4,B1:B0 ; X0*Y1 (don't need upper 32-bits) | |

|| mpy32u .m1x A5,B4,A3:A2 ; X1*Y0 (don't need upper 32-bits) | |

nop | |

nop | |

mv .s1 A0,A4 | |

add .l1x A2,B0,A5 | |

add .s1 A1,A5,A5 | |

ENDPROC(__c6xabi_mpyll) |