diff options
Diffstat (limited to 'sys/gnu/i386/fpemul/reg_u_sub.s')
| -rw-r--r-- | sys/gnu/i386/fpemul/reg_u_sub.s | 357 |
1 files changed, 0 insertions, 357 deletions
diff --git a/sys/gnu/i386/fpemul/reg_u_sub.s b/sys/gnu/i386/fpemul/reg_u_sub.s deleted file mode 100644 index 2a3903a..0000000 --- a/sys/gnu/i386/fpemul/reg_u_sub.s +++ /dev/null @@ -1,357 +0,0 @@ - .file "reg_u_sub.S" -/* - * reg_u_sub.S - * - * Core floating point subtraction routine. - * - * Call from C as: - * void reg_u_sub(FPU_REG *arg1, FPU_REG *arg2, FPU_REG *answ, - * int control_w) - * - * - * 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 subtraction routine reg_u_sub(reg *arg1, reg *arg2, reg *answ). - | Takes two valid reg f.p. numbers (TW_Valid), which are - | treated as unsigned numbers, - | and returns their difference as a TW_Valid or TW_Zero f.p. - | number. - | The first number (arg1) must be the larger. - | The returned number is normalized. - | Basic checks are performed if PARANOID is defined. - */ - -#include <gnu/i386/fpemul/fpu_asm.h> - -.text -ENTRY(reg_u_sub) - pushl %ebp - movl %esp,%ebp - pushl %esi - pushl %edi - pushl %ebx - - movl PARAM1,%esi /* source 1 */ - movl PARAM2,%edi /* source 2 */ - -#ifdef DENORM_OPERAND - cmpl EXP_UNDER,EXP(%esi) - jg xOp1_not_denorm - - call denormal_operand - orl %eax,%eax - jnz FPU_Arith_exit - -xOp1_not_denorm: - cmpl EXP_UNDER,EXP(%edi) - jg xOp2_not_denorm - - call denormal_operand - orl %eax,%eax - jnz FPU_Arith_exit - -xOp2_not_denorm: -#endif /* DENORM_OPERAND */ - -/* xorl %ecx,%ecx */ - movl EXP(%esi),%ecx - subl EXP(%edi),%ecx /* exp1 - exp2 */ - -#ifdef PARANOID - /* source 2 is always smaller than source 1 */ -/* jc L_bugged */ - js L_bugged_1 - - testl $0x80000000,SIGH(%edi) /* The args are assumed to be be normalized */ - je L_bugged_2 - - testl $0x80000000,SIGH(%esi) - je L_bugged_2 -#endif /* PARANOID */ - -/*--------------------------------------+ - | Form a register holding the | - | smaller number | - +--------------------------------------*/ - movl SIGH(%edi),%eax /* register ms word */ - movl SIGL(%edi),%ebx /* register ls word */ - - movl PARAM3,%edi /* destination */ - movl EXP(%esi),%edx - movl %edx,EXP(%edi) /* Copy exponent to destination */ - movb SIGN(%esi),%dl - movb %dl,SIGN(%edi) /* Copy the sign from the first arg */ - - xorl %edx,%edx /* register extension */ - -/*--------------------------------------+ - | Shift the temporary register | - | right the required number of | - | places. | - +--------------------------------------*/ -L_shift_r: - cmpl $32,%ecx /* shrd only works for 0..31 bits */ - jnc L_more_than_31 - -/* less than 32 bits */ - shrd %cl,%ebx,%edx - shrd %cl,%eax,%ebx - shr %cl,%eax - jmp L_shift_done - -L_more_than_31: - cmpl $64,%ecx - jnc L_more_than_63 - - subb $32,%cl - jz L_exactly_32 - - shrd %cl,%eax,%edx - shr %cl,%eax - orl %ebx,%ebx - jz L_more_31_no_low /* none of the lowest bits is set */ - - orl $1,%edx /* record the fact in the extension */ - -L_more_31_no_low: - movl %eax,%ebx - xorl %eax,%eax - jmp L_shift_done - -L_exactly_32: - movl %ebx,%edx - movl %eax,%ebx - xorl %eax,%eax - jmp L_shift_done - -L_more_than_63: - cmpw $65,%cx - jnc L_more_than_64 - - /* Shift right by 64 bits */ - movl %eax,%edx - orl %ebx,%ebx - jz L_more_63_no_low - - orl $1,%edx - jmp L_more_63_no_low - -L_more_than_64: - jne L_more_than_65 - - /* Shift right by 65 bits */ - /* Carry is clear if we get here */ - movl %eax,%edx - rcrl %edx - jnc L_shift_65_nc - - orl $1,%edx - jmp L_more_63_no_low - -L_shift_65_nc: - orl %ebx,%ebx - jz L_more_63_no_low - - orl $1,%edx - jmp L_more_63_no_low - -L_more_than_65: - movl $1,%edx /* The shifted nr always at least one '1' */ - -L_more_63_no_low: - xorl %ebx,%ebx - xorl %eax,%eax - -L_shift_done: -L_subtr: -/*------------------------------+ - | Do the subtraction | - +------------------------------*/ - xorl %ecx,%ecx - subl %edx,%ecx - movl %ecx,%edx - movl SIGL(%esi),%ecx - sbbl %ebx,%ecx - movl %ecx,%ebx - movl SIGH(%esi),%ecx - sbbl %eax,%ecx - movl %ecx,%eax - -#ifdef PARANOID - /* We can never get a borrow */ - jc L_bugged -#endif /* PARANOID */ - -/*--------------------------------------+ - | Normalize the result | - +--------------------------------------*/ - testl $0x80000000,%eax - jnz L_round /* no shifting needed */ - - orl %eax,%eax - jnz L_shift_1 /* shift left 1 - 31 bits */ - - orl %ebx,%ebx - jnz L_shift_32 /* shift left 32 - 63 bits */ - -/* A rare case, the only one which is non-zero if we got here -// is: 1000000 .... 0000 -// -0111111 .... 1111 1 -// -------------------- -// 0000000 .... 0000 1 */ - - cmpl $0x80000000,%edx - jnz L_must_be_zero - - /* Shift left 64 bits */ - subl $64,EXP(%edi) - movl %edx,%eax - jmp L_store - -L_must_be_zero: -#ifdef PARANOID - orl %edx,%edx - jnz L_bugged_3 -#endif /* PARANOID */ - - /* The result is zero */ - movb TW_Zero,TAG(%edi) - movl $0,EXP(%edi) /* exponent */ - movl $0,SIGL(%edi) - movl $0,SIGH(%edi) - jmp L_exit /* Does not underflow */ - -L_shift_32: - movl %ebx,%eax - movl %edx,%ebx - movl $0,%edx - subl $32,EXP(%edi) /* Can get underflow here */ - -/* We need to shift left by 1 - 31 bits */ -L_shift_1: - bsrl %eax,%ecx /* get the required shift in %ecx */ - subl $31,%ecx - negl %ecx - shld %cl,%ebx,%eax - shld %cl,%edx,%ebx - shl %cl,%edx - subl %ecx,EXP(%edi) /* Can get underflow here */ - -L_round: - jmp FPU_round /* Round the result */ - - -#ifdef PARANOID -L_bugged_1: - pushl EX_INTERNAL|0x206 - call EXCEPTION - pop %ebx - jmp L_exit - -L_bugged_2: - pushl EX_INTERNAL|0x209 - call EXCEPTION - pop %ebx - jmp L_exit - -L_bugged_3: - pushl EX_INTERNAL|0x210 - call EXCEPTION - pop %ebx - jmp L_exit - -L_bugged_4: - pushl EX_INTERNAL|0x211 - call EXCEPTION - pop %ebx - jmp L_exit - -L_bugged: - pushl EX_INTERNAL|0x212 - call EXCEPTION - pop %ebx - jmp L_exit -#endif /* PARANOID */ - - -L_store: -/*------------------------------+ - | Store the result | - +------------------------------*/ - movl %eax,SIGH(%edi) - movl %ebx,SIGL(%edi) - - movb TW_Valid,TAG(%edi) /* Set the tags to TW_Valid */ - - cmpl EXP_UNDER,EXP(%edi) - jle L_underflow - -L_exit: - popl %ebx - popl %edi - popl %esi - leave - ret - - -L_underflow: - push %edi - call arith_underflow - pop %ebx - jmp L_exit - |
