/* Copyright (C) 1996, 1997 Free Software Foundation, Inc. Contributed by David Mosberger (davidm@cs.arizona.edu). This file is part of the GNU C Library. The GNU C Library 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. The GNU C Library 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 the GNU C Library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. */ /* The current Alpha chips don't provide hardware for integer division. The C compiler expects the functions __divqu: 64-bit unsigned long divide __remqu: 64-bit unsigned long remainder __divqs/__remqs: signed 64-bit __divlu/__remlu: unsigned 32-bit __divls/__remls: signed 32-bit These are not normal C functions: instead of the normal calling sequence, these expect their arguments in registers t10 and t11, and return the result in t12 (aka pv). Register AT may be clobbered (assembly temporary), anything else must be saved. */ #include <features.h> #ifdef __linux__ # include <asm/gentrap.h> # include <asm/pal.h> #else # include <machine/pal.h> #endif #define mask v0 #define divisor t0 #define compare AT #define tmp1 t2 #define tmp2 t3 #define retaddr t9 #define arg1 t10 #define arg2 t11 #define result t12 #define v0 $0 /* function return value */ #define t0 $1 /* temporary registers (caller-saved) */ #define t1 $2 #define t2 $3 #define t3 $4 #define t4 $5 #define t5 $6 #define t6 $7 #define t7 $8 #define s0 $9 /* saved-registers (callee-saved registers) */ #define s1 $10 #define s2 $11 #define s3 $12 #define s4 $13 #define s5 $14 #define s6 $15 #define fp s6 /* frame-pointer (s6 in frame-less procedures) */ #define a0 $16 /* argument registers (caller-saved) */ #define a1 $17 #define a2 $18 #define a3 $19 #define a4 $20 #define a5 $21 #define t8 $22 /* more temps (caller-saved) */ #define t9 $23 #define t10 $24 #define t11 $25 #define ra $26 /* return address register */ #define t12 $27 #define pv t12 /* procedure-variable register */ #define AT $at /* assembler temporary */ #define gp $29 /* global pointer */ #define sp $30 /* stack pointer */ #define zero $31 /* reads as zero, writes are noops */ #if IS_REM # define DIV_ONLY(x,y...) # define REM_ONLY(x,y...) x,##y # define modulus result # define quotient t1 # define GETSIGN(x) mov arg1, x # define STACK 32 #else # define DIV_ONLY(x,y...) x,##y # define REM_ONLY(x,y...) # define modulus t1 # define quotient result # define GETSIGN(x) xor arg1, arg2, x # define STACK 48 #endif #if SIZE == 8 # define LONGIFY(x,y) mov x,y # define SLONGIFY(x,y) mov x,y # define _SLONGIFY(x) # define NEG(x,y) negq x,y #else # define LONGIFY(x,y) zapnot x,15,y # define SLONGIFY(x,y) sextl x,y # define _SLONGIFY(x) sextl x,x # define NEG(x,y) negl x,y #endif .set noreorder .set noat .ent UFUNC_NAME .globl UFUNC_NAME .align 3 UFUNC_NAME: lda sp, -STACK(sp) .frame sp, STACK, retaddr, 0 .prologue 0 $udiv: stq t0, 0(sp) LONGIFY (arg2, divisor) stq t1, 8(sp) LONGIFY (arg1, modulus) stq v0, 16(sp) clr quotient stq tmp1, 24(sp) ldiq mask, 1 DIV_ONLY(stq tmp2,32(sp)) beq divisor, $divbyzero .align 3 #if SIZE == 8 /* Shift divisor left. */ 1: cmpult divisor, modulus, compare blt divisor, 2f addq divisor, divisor, divisor addq mask, mask, mask bne compare, 1b unop 2: #else /* Shift divisor left using 3-bit shifts as we can't overflow. This results in looping three times less here, but up to two more times later. Thus using a large shift isn't worth it. */ 1: cmpult divisor, modulus, compare s8addq divisor, zero, divisor s8addq mask, zero, mask bne compare, 1b #endif /* Now go back to the right. */ 3: DIV_ONLY(addq quotient, mask, tmp2) srl mask, 1, mask cmpule divisor, modulus, compare subq modulus, divisor, tmp1 DIV_ONLY(cmovne compare, tmp2, quotient) srl divisor, 1, divisor cmovne compare, tmp1, modulus bne mask, 3b $done: ldq t0, 0(sp) ldq t1, 8(sp) ldq v0, 16(sp) ldq tmp1, 24(sp) DIV_ONLY(ldq tmp2, 32(sp)) lda sp, STACK(sp) ret zero, (retaddr), 1 $divbyzero: mov a0, tmp1 ldiq a0, GEN_INTDIV call_pal PAL_gentrap mov tmp1, a0 clr result /* If trap returns, return zero. */ br $done .end UFUNC_NAME .ent SFUNC_NAME .globl SFUNC_NAME .align 3 SFUNC_NAME: lda sp, -STACK(sp) .frame sp, STACK, retaddr, 0 .prologue 0 or arg1, arg2, AT _SLONGIFY(AT) bge AT, $udiv /* don't need to mess with signs */ /* Save originals and find absolute values. */ stq arg1, 0(sp) NEG (arg1, AT) stq arg2, 8(sp) cmovge AT, AT, arg1 stq retaddr, 16(sp) NEG (arg2, AT) stq tmp1, 24(sp) cmovge AT, AT, arg2 /* Do the unsigned division. */ bsr retaddr, UFUNC_NAME /* Restore originals and adjust the sign of the result. */ ldq arg1, 0(sp) ldq arg2, 8(sp) GETSIGN (AT) NEG (result, tmp1) _SLONGIFY(AT) ldq retaddr, 16(sp) cmovlt AT, tmp1, result ldq tmp1, 24(sp) lda sp, STACK(sp) ret zero, (retaddr), 1 .end SFUNC_NAME