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Diffstat (limited to 'sysdeps/alpha/divrem.S')
| -rw-r--r-- | sysdeps/alpha/divrem.S | 169 |
1 files changed, 169 insertions, 0 deletions
diff --git a/sysdeps/alpha/divrem.S b/sysdeps/alpha/divrem.S new file mode 100644 index 0000000000..e6293bf355 --- /dev/null +++ b/sysdeps/alpha/divrem.S @@ -0,0 +1,169 @@ +/* Copyright (C) 1996 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 Library General Public License as +published by the Free Software Foundation; either version 2 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 +Library General Public License for more details. + +You should have received a copy of the GNU Library General Public +License along with the GNU C Library; see the file COPYING.LIB. If +not, write to the Free Software Foundation, Inc., 675 Mass Ave, +Cambridge, MA 02139, 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). Registers AT and v0 may be +clobbered (assembly temporary), anything else must be saved. */ + +#ifdef __linux__ +# include <alpha/regdef.h> +# include <asm/gentrap.h> +# include <asm/pal.h> +#else +# include <regdef.h> +# include <machine/pal.h> +#endif + +#ifdef DEBUG +# define arg1 a0 +# define arg2 a1 +# define result v0 +# define mask t0 +# define tmp0 t1 +# define tmp1 t2 +# define sign t3 +# define retaddr ra +#else +# define arg1 t10 +# define arg2 t11 +# define result t12 +# define mask v0 +# define tmp0 t0 +# define tmp1 t1 +# define sign t2 +# define retaddr t9 +#endif + +# define divisor arg2 +#if IS_REM +# define dividend result +# define quotient arg1 +# define GETDIVIDEND bis arg1,zero,dividend +#else +# define dividend arg1 +# define quotient result +# define GETDIVIDEND +#endif + +#if SIZE == 8 +# define LONGIFYarg1 GETDIVIDEND +# define LONGIFYarg2 +#else +# if SIGNED +# define LONGIFYarg1 addl arg1,zero,dividend +# define LONGIFYarg2 addl arg2,zero,divisor +# else +# define LONGIFYarg1 zapnot arg1,0x0f,dividend +# define LONGIFYarg2 zapnot arg2,0x0f,divisor +# endif +#endif + +#if SIGNED +# define SETSIGN(sign,reg,tmp) subq zero,reg,tmp; cmovlt sign,tmp,reg +# if IS_REM +# define GETSIGN(x,y,s) bis x,zero,s +# else +# define GETSIGN(x,y,s) xor x,y,s +# endif +#else +# define SETSIGN(sign,reg,tmp) +# define GETSIGN(x,y,s) +#endif + + .set noreorder + .set noat + + .ent FUNC_NAME + .globl FUNC_NAME + + .align 5 +FUNC_NAME: +# define FRAME_SIZE 0x30 + .frame sp,FRAME_SIZE,ra,0 + lda sp,-FRAME_SIZE(sp) + .prologue 1 + stq arg1,0x00(sp) + LONGIFYarg1 + stq arg2,0x08(sp) + LONGIFYarg2 + stq mask,0x10(sp) + bis zero,1,mask + stq tmp0,0x18(sp) + bis zero,zero,quotient + stq tmp1,0x20(sp) + beq divisor,divbyzero + stq sign,0x28(sp) + GETSIGN(dividend,divisor,sign) +#if SIGNED + subq zero,dividend,tmp0 + subq zero,divisor,tmp1 + cmovlt dividend,tmp0,dividend + cmovlt divisor,tmp1,divisor +#endif + /* + * Shift divisor left until either bit 63 is set or until it + * is at least as big as the dividend: + */ + .align 3 +1: cmpule dividend,divisor,AT + blt divisor,2f + blbs AT,2f + addq mask,mask,mask + addq divisor,divisor,divisor + br 1b + + .align 3 +2: addq mask,quotient,tmp0 + cmpule divisor,dividend,AT + subq dividend,divisor,tmp1 + srl divisor,1,divisor + srl mask,1,mask + cmovlbs AT,tmp0,quotient + cmovlbs AT,tmp1,dividend + bne mask,2b + + ldq arg1,0x00(sp) + SETSIGN(sign,result,tmp0) +done: ldq arg2,0x08(sp) + ldq mask,0x10(sp) + ldq tmp0,0x18(sp) + ldq tmp1,0x20(sp) + ldq sign,0x28(sp) + lda sp,FRAME_SIZE(sp) + ret zero,(retaddr),0 + +divbyzero: + lda a0,GEN_INTDIV(zero) + call_pal PAL_gentrap + bis zero,zero,result /* if trap returns, return 0 */ + ldq arg1,0x00(sp) + br done + + .end FUNC_NAME |