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Diffstat (limited to 'sys/gnu/i386/fpemul/reg_u_div.s')
| -rw-r--r-- | sys/gnu/i386/fpemul/reg_u_div.s | 501 |
1 files changed, 0 insertions, 501 deletions
diff --git a/sys/gnu/i386/fpemul/reg_u_div.s b/sys/gnu/i386/fpemul/reg_u_div.s deleted file mode 100644 index 6a0850d..0000000 --- a/sys/gnu/i386/fpemul/reg_u_div.s +++ /dev/null @@ -1,501 +0,0 @@ - .file "reg_u_div.S" -/* - * reg_u_div.S - * - * Core division routines - * - * - * Copyright (C) 1992,1993,1994 - * W. Metzenthen, 22 Parker St, Ormond, Vic 3163, - * Australia. E-mail billm@vaxc.cc.monash.edu.au - * All rights reserved. - * - * This copyright notice covers the redistribution and use of the - * FPU emulator developed by W. Metzenthen. It covers only its use - * in the 386BSD, FreeBSD and NetBSD operating systems. Any other - * use is not permitted under this copyright. - * - * Redistribution and use in source and binary forms, with or without - * modification, are permitted provided that the following conditions - * are met: - * 1. Redistributions of source code must retain the above copyright - * notice, this list of conditions and the following disclaimer. - * 2. Redistributions in binary form must include information specifying - * that source code for the emulator is freely available and include - * either: - * a) an offer to provide the source code for a nominal distribution - * fee, or - * b) list at least two alternative methods whereby the source - * can be obtained, e.g. a publically accessible bulletin board - * and an anonymous ftp site from which the software can be - * downloaded. - * 3. All advertising materials specifically mentioning features or use of - * this emulator must acknowledge that it was developed by W. Metzenthen. - * 4. The name of W. Metzenthen may not be used to endorse or promote - * products derived from this software without specific prior written - * permission. - * - * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, - * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY - * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL - * W. METZENTHEN BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, - * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, - * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR - * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF - * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING - * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS - * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. - * - * - * The purpose of this copyright, based upon the Berkeley copyright, is to - * ensure that the covered software remains freely available to everyone. - * - * The software (with necessary differences) is also available, but under - * the terms of the GNU copyleft, for the Linux operating system and for - * the djgpp ms-dos extender. - * - * W. Metzenthen June 1994. - * - * - * $FreeBSD$ - * - */ - -/*---------------------------------------------------------------------------+ - | Kernel for the division routines. | - | | - | void reg_u_div(FPU_REG *a, FPU_REG *a, | - | FPU_REG *dest, unsigned int control_word) | - | | - | Does not compute the destination exponent, but does adjust it. | - +---------------------------------------------------------------------------*/ - -#include <gnu/i386/fpemul/fpu_asm.h> - - -/* #define dSIGL(x) (x) */ -/* #define dSIGH(x) 4(x) */ - - -.data -/* - Local storage: - Result: accum_3:accum_2:accum_1:accum_0 - Overflow flag: ovfl_flag - */ - ALIGN_DATA -accum_3: - .long 0 -accum_2: - .long 0 -accum_1: - .long 0 -accum_0: - .long 0 -result_1: - .long 0 -result_2: - .long 0 -ovfl_flag: - .byte 0 - - -.text - -.globl divide_kernel - -ENTRY(reg_u_div) - pushl %ebp - movl %esp,%ebp - - pushl %esi - pushl %edi - pushl %ebx - - movl PARAM1,%esi /* pointer to num */ - movl PARAM2,%ebx /* pointer to denom */ - movl PARAM3,%edi /* pointer to answer */ - -#ifdef DENORM_OPERAND - movl EXP(%esi),%eax - cmpl EXP_UNDER,%eax - jg xOp1_not_denorm - - call denormal_operand - orl %eax,%eax - jnz FPU_Arith_exit - -xOp1_not_denorm: - movl EXP(%ebx),%eax - cmpl EXP_UNDER,%eax - jg xOp2_not_denorm - - call denormal_operand - orl %eax,%eax - jnz FPU_Arith_exit - -xOp2_not_denorm: -#endif /* DENORM_OPERAND */ - -divide_kernel: -#ifdef PARANOID -/* testl $0x80000000, SIGH(%esi) *//* Dividend */ -/* je L_bugged */ - testl $0x80000000, SIGH(%ebx) /* Divisor*/ - je L_bugged -#endif /* PARANOID */ - -/* Check if the divisor can be treated as having just 32 bits */ - cmpl $0,SIGL(%ebx) - jnz L_Full_Division /* Can't do a quick divide */ - -/* We should be able to zip through the division here */ - movl SIGH(%ebx),%ecx /* The divisor */ - movl SIGH(%esi),%edx /* Dividend */ - movl SIGL(%esi),%eax /* Dividend */ - - cmpl %ecx,%edx - setaeb ovfl_flag /* Keep a record */ - jb L_no_adjust - - subl %ecx,%edx /* Prevent the overflow */ - -L_no_adjust: - /* Divide the 64 bit number by the 32 bit denominator */ - divl %ecx - movl %eax,result_2 - - /* Work on the remainder of the first division */ - xorl %eax,%eax - divl %ecx - movl %eax,result_1 - - /* Work on the remainder of the 64 bit division */ - xorl %eax,%eax - divl %ecx - - testb $255,ovfl_flag /* was the num > denom ? */ - je L_no_overflow - - /* Do the shifting here */ - /* increase the exponent */ - incl EXP(%edi) - - /* shift the mantissa right one bit */ - stc /* To set the ms bit */ - rcrl result_2 - rcrl result_1 - rcrl %eax - -L_no_overflow: - jmp LRound_precision /* Do the rounding as required*/ - - -/*---------------------------------------------------------------------------+ - | Divide: Return arg1/arg2 to arg3. | - | | - | This routine does not use the exponents of arg1 and arg2, but does | - | adjust the exponent of arg3. | - | | - | The maximum returned value is (ignoring exponents) | - | .ffffffff ffffffff | - | ------------------ = 1.ffffffff fffffffe | - | .80000000 00000000 | - | and the minimum is | - | .80000000 00000000 | - | ------------------ = .80000000 00000001 (rounded) | - | .ffffffff ffffffff | - | | - +---------------------------------------------------------------------------*/ - - -L_Full_Division: - /* Save extended dividend in local register*/ - movl SIGL(%esi),%eax - movl %eax,accum_2 - movl SIGH(%esi),%eax - movl %eax,accum_3 - xorl %eax,%eax - movl %eax,accum_1 /* zero the extension */ - movl %eax,accum_0 /* zero the extension */ - - movl SIGL(%esi),%eax /* Get the current num */ - movl SIGH(%esi),%edx - -/*----------------------------------------------------------------------*/ -/* Initialization done */ -/* Do the first 32 bits */ - - movb $0,ovfl_flag - cmpl SIGH(%ebx),%edx /* Test for imminent overflow */ - jb LLess_than_1 - ja LGreater_than_1 - - cmpl SIGL(%ebx),%eax - jb LLess_than_1 - -LGreater_than_1: -/* The dividend is greater or equal, would cause overflow */ - setaeb ovfl_flag /* Keep a record */ - - subl SIGL(%ebx),%eax - sbbl SIGH(%ebx),%edx /* Prevent the overflow */ - movl %eax,accum_2 - movl %edx,accum_3 - -LLess_than_1: -/* At this point, we have a dividend < divisor, with a record of - adjustment in ovfl_flag */ - - /* We will divide by a number which is too large */ - movl SIGH(%ebx),%ecx - addl $1,%ecx - jnc LFirst_div_not_1 - - /* here we need to divide by 100000000h, - i.e., no division at all.. */ - mov %edx,%eax - jmp LFirst_div_done - -LFirst_div_not_1: - divl %ecx /* Divide the numerator by the augmented - denom ms dw */ - -LFirst_div_done: - movl %eax,result_2 /* Put the result in the answer */ - - mull SIGH(%ebx) /* mul by the ms dw of the denom */ - - subl %eax,accum_2 /* Subtract from the num local reg */ - sbbl %edx,accum_3 - - movl result_2,%eax /* Get the result back */ - mull SIGL(%ebx) /* now mul the ls dw of the denom */ - - subl %eax,accum_1 /* Subtract from the num local reg */ - sbbl %edx,accum_2 - sbbl $0,accum_3 - je LDo_2nd_32_bits /* Must check for non-zero result here */ - -#ifdef PARANOID - jb L_bugged_1 -#endif /* PARANOID */ - - /* need to subtract another once of the denom */ - incl result_2 /* Correct the answer */ - - movl SIGL(%ebx),%eax - movl SIGH(%ebx),%edx - subl %eax,accum_1 /* Subtract from the num local reg */ - sbbl %edx,accum_2 - -#ifdef PARANOID - sbbl $0,accum_3 - jne L_bugged_1 /* Must check for non-zero result here */ -#endif /* PARANOID */ - -/*----------------------------------------------------------------------*/ -/* Half of the main problem is done, there is just a reduced numerator - to handle now */ -/* Work with the second 32 bits, accum_0 not used from now on */ -LDo_2nd_32_bits: - movl accum_2,%edx /* get the reduced num */ - movl accum_1,%eax - - /* need to check for possible subsequent overflow */ - cmpl SIGH(%ebx),%edx - jb LDo_2nd_div - ja LPrevent_2nd_overflow - - cmpl SIGL(%ebx),%eax - jb LDo_2nd_div - -LPrevent_2nd_overflow: -/* The numerator is greater or equal, would cause overflow */ - /* prevent overflow */ - subl SIGL(%ebx),%eax - sbbl SIGH(%ebx),%edx - movl %edx,accum_2 - movl %eax,accum_1 - - incl result_2 /* Reflect the subtraction in the answer */ - -#ifdef PARANOID - je L_bugged_2 /* Can't bump the result to 1.0 */ -#endif /* PARANOID */ - -LDo_2nd_div: - cmpl $0,%ecx /* augmented denom msw*/ - jnz LSecond_div_not_1 - - /* %ecx == 0, we are dividing by 1.0 */ - mov %edx,%eax - jmp LSecond_div_done - -LSecond_div_not_1: - divl %ecx /* Divide the numerator by the denom ms dw */ - -LSecond_div_done: - movl %eax,result_1 /* Put the result in the answer */ - - mull SIGH(%ebx) /* mul by the ms dw of the denom */ - - subl %eax,accum_1 /* Subtract from the num local reg */ - sbbl %edx,accum_2 - -#ifdef PARANOID - jc L_bugged_2 -#endif /* PARANOID */ - - movl result_1,%eax /* Get the result back */ - mull SIGL(%ebx) /* now mul the ls dw of the denom */ - - subl %eax,accum_0 /* Subtract from the num local reg */ - sbbl %edx,accum_1 /* Subtract from the num local reg */ - sbbl $0,accum_2 - -#ifdef PARANOID - jc L_bugged_2 -#endif /* PARANOID */ - - jz LDo_3rd_32_bits - -#ifdef PARANOID - cmpl $1,accum_2 - jne L_bugged_2 -#endif /* PARANOID */ - - /* need to subtract another once of the denom */ - movl SIGL(%ebx),%eax - movl SIGH(%ebx),%edx - subl %eax,accum_0 /* Subtract from the num local reg */ - sbbl %edx,accum_1 - sbbl $0,accum_2 - -#ifdef PARANOID - jc L_bugged_2 - jne L_bugged_2 -#endif /* PARANOID */ - - addl $1,result_1 /* Correct the answer */ - adcl $0,result_2 - -#ifdef PARANOID - jc L_bugged_2 /* Must check for non-zero result here */ -#endif /* PARANOID */ - -/*----------------------------------------------------------------------*/ -/* The division is essentially finished here, we just need to perform - tidying operations. */ -/* deal with the 3rd 32 bits */ -LDo_3rd_32_bits: - movl accum_1,%edx /* get the reduced num */ - movl accum_0,%eax - - /* need to check for possible subsequent overflow */ - cmpl SIGH(%ebx),%edx /* denom*/ - jb LRound_prep - ja LPrevent_3rd_overflow - - cmpl SIGL(%ebx),%eax /* denom */ - jb LRound_prep - -LPrevent_3rd_overflow: - /* prevent overflow */ - subl SIGL(%ebx),%eax - sbbl SIGH(%ebx),%edx - movl %edx,accum_1 - movl %eax,accum_0 - - addl $1,result_1 /* Reflect the subtraction in the answer */ - adcl $0,result_2 - jne LRound_prep - jnc LRound_prep - - /* This is a tricky spot, there is an overflow of the answer */ - movb $255,ovfl_flag /* Overflow -> 1.000 */ - -LRound_prep: -/* Prepare for rounding. -// To test for rounding, we just need to compare 2*accum with the -// denom. */ - movl accum_0,%ecx - movl accum_1,%edx - movl %ecx,%eax - orl %edx,%eax - jz LRound_ovfl /* The accumulator contains zero.*/ - - /* Multiply by 2 */ - clc - rcll $1,%ecx - rcll $1,%edx - jc LRound_large /* No need to compare, denom smaller */ - - subl SIGL(%ebx),%ecx - sbbl SIGH(%ebx),%edx - jnc LRound_not_small - - movl $0x70000000,%eax /* Denom was larger */ - jmp LRound_ovfl - -LRound_not_small: - jnz LRound_large - - movl $0x80000000,%eax /* Remainder was exactly 1/2 denom */ - jmp LRound_ovfl - -LRound_large: - movl $0xff000000,%eax /* Denom was smaller */ - -LRound_ovfl: -/* We are now ready to deal with rounding, but first we must get - the bits properly aligned */ - testb $255,ovfl_flag /* was the num > denom ? */ - je LRound_precision - - incl EXP(%edi) - - /* shift the mantissa right one bit */ - stc /* Will set the ms bit */ - rcrl result_2 - rcrl result_1 - rcrl %eax - -/* Round the result as required */ -LRound_precision: - decl EXP(%edi) /* binary point between 1st & 2nd bits */ - - movl %eax,%edx - movl result_1,%ebx - movl result_2,%eax - jmp FPU_round - - -#ifdef PARANOID -/* The logic is wrong if we got here */ -L_bugged: - pushl EX_INTERNAL|0x202 - call EXCEPTION - pop %ebx - jmp L_exit - -L_bugged_1: - pushl EX_INTERNAL|0x203 - call EXCEPTION - pop %ebx - jmp L_exit - -L_bugged_2: - pushl EX_INTERNAL|0x204 - call EXCEPTION - pop %ebx - jmp L_exit - -L_exit: - popl %ebx - popl %edi - popl %esi - - leave - ret -#endif /* PARANOID */ |
