+++ /dev/null
-/* DEC Alpha division and remainder support.
- Copyright (C) 1994, 1999 Free Software Foundation, Inc.
-
-This file 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, or (at your option) any
-later version.
-
-In addition to the permissions in the GNU General Public License, the
-Free Software Foundation gives you unlimited permission to link the
-compiled version of this file into combinations with other programs,
-and to distribute those combinations without any restriction coming
-from the use of this file. (The General Public License restrictions
-do apply in other respects; for example, they cover modification of
-the file, and distribution when not linked into a combine
-executable.)
-
-This file 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; see the file COPYING. If not, write to
-the Free Software Foundation, 59 Temple Place - Suite 330,
-Boston, MA 02111-1307, USA. */
-
-/* This had to be written in assembler because the division functions
- use a non-standard calling convention.
-
- This file provides an implementation of __divqu, __divq, __divlu,
- __divl, __remqu, __remq, __remlu and __reml. CPP macros control
- the exact operation.
-
- Operation performed: $27 := $24 o $25, clobber $28, return address to
- caller in $23, where o one of the operations.
-
- The following macros need to be defined:
-
- SIZE, the number of bits, 32 or 64.
-
- TYPE, either UNSIGNED or SIGNED
-
- OPERATION, either DIVISION or REMAINDER
-
- SPECIAL_CALLING_CONVENTION, 0 or 1. It is useful for debugging to
- define this to 0. That removes the `__' prefix to make the function
- name not collide with the existing libc.a names, and uses the
- standard Alpha procedure calling convention.
-*/
-
-#ifndef SPECIAL_CALLING_CONVENTION
-#define SPECIAL_CALLING_CONVENTION 1
-#endif
-
-#ifdef L_divl
-#if SPECIAL_CALLING_CONVENTION
-#define FUNCTION_NAME __divl
-#else
-#define FUNCTION_NAME divl
-#endif
-#define SIZE 32
-#define TYPE SIGNED
-#define OPERATION DIVISION
-#endif
-
-#ifdef L_divlu
-#if SPECIAL_CALLING_CONVENTION
-#define FUNCTION_NAME __divlu
-#else
-#define FUNCTION_NAME divlu
-#endif
-#define SIZE 32
-#define TYPE UNSIGNED
-#define OPERATION DIVISION
-#endif
-
-#ifdef L_divq
-#if SPECIAL_CALLING_CONVENTION
-#define FUNCTION_NAME __divq
-#else
-#define FUNCTION_NAME divq
-#endif
-#define SIZE 64
-#define TYPE SIGNED
-#define OPERATION DIVISION
-#endif
-
-#ifdef L_divqu
-#if SPECIAL_CALLING_CONVENTION
-#define FUNCTION_NAME __divqu
-#else
-#define FUNCTION_NAME divqu
-#endif
-#define SIZE 64
-#define TYPE UNSIGNED
-#define OPERATION DIVISION
-#endif
-
-#ifdef L_reml
-#if SPECIAL_CALLING_CONVENTION
-#define FUNCTION_NAME __reml
-#else
-#define FUNCTION_NAME reml
-#endif
-#define SIZE 32
-#define TYPE SIGNED
-#define OPERATION REMAINDER
-#endif
-
-#ifdef L_remlu
-#if SPECIAL_CALLING_CONVENTION
-#define FUNCTION_NAME __remlu
-#else
-#define FUNCTION_NAME remlu
-#endif
-#define SIZE 32
-#define TYPE UNSIGNED
-#define OPERATION REMAINDER
-#endif
-
-#ifdef L_remq
-#if SPECIAL_CALLING_CONVENTION
-#define FUNCTION_NAME __remq
-#else
-#define FUNCTION_NAME remq
-#endif
-#define SIZE 64
-#define TYPE SIGNED
-#define OPERATION REMAINDER
-#endif
-
-#ifdef L_remqu
-#if SPECIAL_CALLING_CONVENTION
-#define FUNCTION_NAME __remqu
-#else
-#define FUNCTION_NAME remqu
-#endif
-#define SIZE 64
-#define TYPE UNSIGNED
-#define OPERATION REMAINDER
-#endif
-
-#define tmp0 $3
-#define tmp1 $28
-#define cnt $1
-#define result_sign $2
-
-#if SPECIAL_CALLING_CONVENTION
-#define N $24
-#define D $25
-#define Q RETREG
-#define RETREG $27
-#else
-#define N $16
-#define D $17
-#define Q RETREG
-#define RETREG $0
-#endif
-
-/* Misc symbols to make alpha assembler easier to read. */
-#define zero $31
-#define sp $30
-
-/* Symbols to make interface nicer. */
-#define UNSIGNED 0
-#define SIGNED 1
-#define DIVISION 0
-#define REMAINDER 1
-
- .set noreorder
- .set noat
-.text
- .align 3
- .globl FUNCTION_NAME
- .ent FUNCTION_NAME
-FUNCTION_NAME:
-
- .frame $30,0,$26,0
- .prologue 0
-
-/* Under the special calling convention, we have to preserve all register
- values but $23 and $28. */
-#if SPECIAL_CALLING_CONVENTION
- lda sp,-64(sp)
-#if OPERATION == DIVISION
- stq N,0(sp)
-#endif
- stq D,8(sp)
- stq cnt,16(sp)
- stq result_sign,24(sp)
- stq tmp0,32(sp)
-#endif
-
-/* If we are computing the remainder, move N to the register that is used
- for the return value, and redefine what register is used for N. */
-#if OPERATION == REMAINDER
- bis N,N,RETREG
-#undef N
-#define N RETREG
-#endif
-
-/* Perform conversion from 32 bit types to 64 bit types. */
-#if SIZE == 32
-#if TYPE == SIGNED
- /* If there are problems with the signed case, add these instructions.
- The caller should already have done this.
- addl N,0,N # sign extend N
- addl D,0,D # sign extend D
- */
-#else /* UNSIGNED */
- zap N,0xf0,N # zero extend N (caller required to sign extend)
- zap D,0xf0,D # zero extend D
-#endif
-#endif
-
-/* Check for divide by zero. */
- bne D,$34
- lda $16,-2(zero)
- call_pal 0xaa
-$34:
-
-#if TYPE == SIGNED
-#if OPERATION == DIVISION
- xor N,D,result_sign
-#else
- bis N,N,result_sign
-#endif
-/* Get the absolute values of N and D. */
- subq zero,N,tmp0
- cmovlt N,tmp0,N
- subq zero,D,tmp0
- cmovlt D,tmp0,D
-#endif
-
-/* Compute CNT = ceil(log2(N)) - ceil(log2(D)). This is the number of
- divide iterations we will have to perform. Should you wish to optimize
- this, check a few bits at a time, preferably using zap/zapnot. Be
- careful though, this code runs fast fro the most common cases, when the
- quotient is small. */
- bge N,$35
- bis zero,1,cnt
- blt D,$40
- .align 3
-$39: addq D,D,D
- addl cnt,1,cnt
- bge D,$39
- br zero,$40
-$35: cmpult N,D,tmp0
- bis zero,zero,cnt
- bne tmp0,$42
- .align 3
-$44: addq D,D,D
- cmpult N,D,tmp0
- addl cnt,1,cnt
- beq tmp0,$44
-$42: srl D,1,D
-$40:
- subl cnt,1,cnt
-
-
-/* Actual divide. Could be optimized with unrolling. */
-#if OPERATION == DIVISION
- bis zero,zero,Q
-#endif
- blt cnt,$46
- .align 3
-$49: cmpule D,N,tmp1
- subq N,D,tmp0
- srl D,1,D
- subl cnt,1,cnt
- cmovne tmp1,tmp0,N
-#if OPERATION == DIVISION
- addq Q,Q,Q
- bis Q,tmp1,Q
-#endif
- bge cnt,$49
-$46:
-
-
-/* The result is now in RETREG. NOTE! It was written to RETREG using
- either N or Q as a synonym! */
-
-
-/* Change the sign of the result as needed. */
-#if TYPE == SIGNED
- subq zero,RETREG,tmp0
- cmovlt result_sign,tmp0,RETREG
-#endif
-
-
-/* Restore clobbered registers. */
-#if SPECIAL_CALLING_CONVENTION
-#if OPERATION == DIVISION
- ldq N,0(sp)
-#endif
- ldq D,8(sp)
- ldq cnt,16(sp)
- ldq result_sign,24(sp)
- ldq tmp0,32(sp)
-
- lda sp,64(sp)
-#endif
-
-
-/* Sign extend an *unsigned* 32 bit result, as required by the Alpha
- conventions. */
-#if TYPE == UNSIGNED && SIZE == 32
- /* This could be avoided by adding some CPP hair to the divide loop.
- It is probably not worth the added complexity. */
- addl RETREG,0,RETREG
-#endif
-
-
-#if SPECIAL_CALLING_CONVENTION
- ret zero,($23),1
-#else
- ret zero,($26),1
-#endif
- .end FUNCTION_NAME
projects / msp430-gcc.git / blobdiff