nest-open-source / nest-learning-thermostat / 5.1.8 / libgcrypt / refs/heads/master / . / libgcrypt-1.4.6 / mpi / m68k / mpih-sub1.S

/* mc68020 __mpn_sub_n -- Subtract two limb vectors of the same length > 0 and | |

* store difference in a third limb vector. | |

* | |

* Copyright (C) 1992, 1994, 1996, 1998, | |

* 2001, 2002 Free Software Foundation, Inc. | |

* | |

* This file is part of Libgcrypt. | |

* | |

* Libgcrypt is free software; you can redistribute it and/or modify | |

* it under the terms of the GNU Lesser General Public License as | |

* published by the Free Software Foundation; either version 2.1 of | |

* the License, or (at your option) any later version. | |

* | |

* Libgcrypt 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 Lesser General Public License for more details. | |

* | |

* You should have received a copy of the GNU Lesser 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 | |

* | |

* Note: This code is heavily based on the GNU MP Library. | |

* Actually it's the same code with only minor changes in the | |

* way the data is stored; this is to support the abstraction | |

* of an optional secure memory allocation which may be used | |

* to avoid revealing of sensitive data due to paging etc. | |

*/ | |

#include "sysdep.h" | |

#include "asm-syntax.h" | |

/******************* | |

* mpi_limb_t | |

* _gcry_mpih_sub_n( mpi_ptr_t res_ptr, (sp + 4) | |

* mpi_ptr_t s1_ptr, (sp + 8) | |

* mpi_ptr_t s2_ptr, (sp + 16) | |

* mpi_size_t size) (sp + 12) | |

*/ | |

TEXT | |

ALIGN | |

GLOBL C_SYMBOL_NAME(_gcry_mpih_sub_n) | |

C_SYMBOL_NAME(_gcry_mpih_sub_n:) | |

PROLOG(_gcry_mpih_sub_n) | |

/* Save used registers on the stack. */ | |

movel R(d2),MEM_PREDEC(sp) | |

movel R(a2),MEM_PREDEC(sp) | |

/* Copy the arguments to registers. Better use movem? */ | |

movel MEM_DISP(sp,12),R(a2) | |

movel MEM_DISP(sp,16),R(a0) | |

movel MEM_DISP(sp,20),R(a1) | |

movel MEM_DISP(sp,24),R(d2) | |

eorw #1,R(d2) | |

lsrl #1,R(d2) | |

bcc L(L1) | |

subql #1,R(d2) /* clears cy as side effect */ | |

L(Loop:) | |

movel MEM_POSTINC(a0),R(d0) | |

movel MEM_POSTINC(a1),R(d1) | |

subxl R(d1),R(d0) | |

movel R(d0),MEM_POSTINC(a2) | |

L(L1:) movel MEM_POSTINC(a0),R(d0) | |

movel MEM_POSTINC(a1),R(d1) | |

subxl R(d1),R(d0) | |

movel R(d0),MEM_POSTINC(a2) | |

dbf R(d2),L(Loop) /* loop until 16 lsb of %4 == -1 */ | |

subxl R(d0),R(d0) /* d0 <= -cy; save cy as 0 or -1 in d0 */ | |

subl #0x10000,R(d2) | |

bcs L(L2) | |

addl R(d0),R(d0) /* restore cy */ | |

bra L(Loop) | |

L(L2:) | |

negl R(d0) | |

/* Restore used registers from stack frame. */ | |

movel MEM_POSTINC(sp),R(a2) | |

movel MEM_POSTINC(sp),R(d2) | |

rts | |

EPILOG(_gcry_mpih_sub_n) | |