.file "reg_u_add.S" /* * reg_u_add.S * * Add two valid (TW_Valid) FPU_REG numbers, of the same sign, and put the * result in a destination FPU_REG. * * Call from C as: * void reg_u_add(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. * * * $Id$ * */ /* | Kernel addition routine reg_u_add(reg *arg1, reg *arg2, reg *answ). | Takes two valid reg f.p. numbers (TW_Valid), which are | treated as unsigned numbers, | and returns their sum as a TW_Valid or TW_S f.p. number. | The returned number is normalized. | Basic checks are performed if PARANOID is defined. */ #include #include #include .text .align 2,144 .globl _reg_u_add _reg_u_add: pushl %ebp movl %esp,%ebp /* subl $16,%esp*/ 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 */ /* jnc L_arg1_larger*/ jge L_arg1_larger /* num1 is smaller */ movl SIGL(%esi),%ebx movl SIGH(%esi),%eax movl %edi,%esi negw %cx jmp L_accum_loaded L_arg1_larger: /* num1 has larger or equal exponent */ movl SIGL(%edi),%ebx movl SIGH(%edi),%eax L_accum_loaded: movl PARAM3,%edi /* destination */ movb SIGN(%esi),%dl movb %dl,SIGN(%edi) /* Copy the sign from the first arg */ movl EXP(%esi),%edx movl %edx,EXP(%edi) /* Copy exponent to destination */ xorl %edx,%edx /* clear the extension */ #ifdef PARANOID testl $0x80000000,%eax je L_bugged testl $0x80000000,SIGH(%esi) je L_bugged #endif PARANOID /* The number to be shifted is in %eax:%ebx:%edx*/ cmpw $32,%cx /* 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: cmpw $64,%cx 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 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: 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: /* Now do the addition */ addl SIGL(%esi),%ebx adcl SIGH(%esi),%eax jnc L_round_the_result /* Overflow, adjust the result */ rcrl $1,%eax rcrl $1,%ebx rcrl $1,%edx jnc L_no_bit_lost orl $1,%edx L_no_bit_lost: incl EXP(%edi) L_round_the_result: jmp FPU_round /* Round the result*/ #ifdef PARANOID /* If we ever get here then we have problems! */ L_bugged: pushl EX_INTERNAL|0x201 call EXCEPTION pop %ebx jmp L_exit #endif PARANOID L_exit: popl %ebx popl %edi popl %esi leave ret