.file "reg_div.S" /* $OpenBSD: reg_div.s,v 1.3 2003/04/17 03:45:30 drahn Exp $ */ /* * reg_div.S * * Divide one FPU_REG by another and put the result in a destination FPU_REG. * * Call from C as: * void reg_div(FPU_REG *a, FPU_REG *b, FPU_REG *dest, * * * 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: reg_div.s,v 1.3 1994/06/10 07:44:50 rich Exp $ * */ #include #include #include #include .text #ifdef __ELF__ .align 4 #else .align 2 #endif .globl _C_LABEL(reg_div) _C_LABEL(reg_div): pushl %ebp movl %esp,%ebp pushl %esi pushl %edi pushl %ebx movl PARAM1,%esi movl PARAM2,%ebx movl PARAM3,%edi movb TAG(%esi),%al orb TAG(%ebx),%al jne L_div_special /* Not (both numbers TW_Valid) */ #ifdef DENORM_OPERAND /* Check for denormals */ cmpl EXP_UNDER,EXP(%esi) jg xL_arg1_not_denormal call _C_LABEL(denormal_operand) orl %eax,%eax jnz FPU_Arith_exit xL_arg1_not_denormal: cmpl EXP_UNDER,EXP(%ebx) jg xL_arg2_not_denormal call _C_LABEL(denormal_operand) orl %eax,%eax jnz FPU_Arith_exit xL_arg2_not_denormal: #endif DENORM_OPERAND /* Both arguments are TW_Valid */ movb TW_Valid,TAG(%edi) movb SIGN(%esi),%cl cmpb %cl,SIGN(%ebx) setne (%edi) /* Set the sign, requires SIGN_NEG=1, SIGN_POS=0 */ movl EXP(%esi),%edx movl EXP(%ebx),%eax subl %eax,%edx addl EXP_BIAS,%edx movl %edx,EXP(%edi) jmp _C_LABEL(divide_kernel) /*-----------------------------------------------------------------------*/ L_div_special: cmpb TW_NaN,TAG(%esi) /* A NaN with anything to give NaN */ je L_arg1_NaN cmpb TW_NaN,TAG(%ebx) /* A NaN with anything to give NaN */ jne L_no_NaN_arg /* Operations on NaNs */ L_arg1_NaN: L_arg2_NaN: pushl %edi /* Destination */ pushl %ebx pushl %esi call _C_LABEL(real_2op_NaN) jmp LDiv_exit /* Invalid operations */ L_zero_zero: L_inf_inf: pushl %edi /* Destination */ call _C_LABEL(arith)_invalid /* 0/0 or Infinity/Infinity */ jmp LDiv_exit L_no_NaN_arg: cmpb TW_Infinity,TAG(%esi) jne L_arg1_not_inf cmpb TW_Infinity,TAG(%ebx) je L_inf_inf /* invalid operation */ cmpb TW_Valid,TAG(%ebx) je L_inf_valid #ifdef PARANOID /* arg2 must be zero or valid */ cmpb TW_Zero,TAG(%ebx) ja L_unknown_tags #endif PARANOID /* Note that p16-9 says that infinity/0 returns infinity */ jmp L_copy_arg1 /* Answer is Inf */ L_inf_valid: #ifdef DENORM_OPERAND cmpl EXP_UNDER,EXP(%ebx) jg L_copy_arg1 /* Answer is Inf */ call _C_LABEL(denormal_operand) orl %eax,%eax jnz FPU_Arith_exit #endif DENORM_OPERAND jmp L_copy_arg1 /* Answer is Inf */ L_arg1_not_inf: cmpb TW_Zero,TAG(%ebx) /* Priority to div-by-zero error */ jne L_arg2_not_zero cmpb TW_Zero,TAG(%esi) je L_zero_zero /* invalid operation */ #ifdef PARANOID /* arg1 must be valid */ cmpb TW_Valid,TAG(%esi) ja L_unknown_tags #endif PARANOID /* Division by zero error */ pushl %edi /* destination */ movb SIGN(%esi),%al xorb SIGN(%ebx),%al pushl %eax /* lower 8 bits have the sign */ call _C_LABEL(divide_by_zero) jmp LDiv_exit L_arg2_not_zero: cmpb TW_Infinity,TAG(%ebx) jne L_arg2_not_inf #ifdef DENORM_OPERAND cmpb TW_Valid,TAG(%esi) jne L_return_zero cmpl EXP_UNDER,EXP(%esi) jg L_return_zero /* Answer is zero */ call _C_LABEL(denormal_operand) orl %eax,%eax jnz FPU_Arith_exit #endif DENORM_OPERAND jmp L_return_zero /* Answer is zero */ L_arg2_not_inf: #ifdef PARANOID cmpb TW_Zero,TAG(%esi) jne L_unknown_tags #endif PARANOID /* arg1 is zero, arg2 is not Infinity or a NaN */ #ifdef DENORM_OPERAND cmpl EXP_UNDER,EXP(%ebx) jg L_copy_arg1 /* Answer is zero */ call _C_LABEL(denormal_operand) orl %eax,%eax jnz FPU_Arith_exit #endif DENORM_OPERAND L_copy_arg1: movb TAG(%esi),%al movb %al,TAG(%edi) movl EXP(%esi),%eax movl %eax,EXP(%edi) movl SIGL(%esi),%eax movl %eax,SIGL(%edi) movl SIGH(%esi),%eax movl %eax,SIGH(%edi) movb SIGN(%esi),%cl cmpb %cl,SIGN(%ebx) jne LDiv_negative_result movb SIGN_POS,SIGN(%edi) jmp LDiv_exit LDiv_set_result_sign: movb SIGN(%esi),%cl cmpb %cl,SIGN(%edi) jne LDiv_negative_result movb SIGN_POS,SIGN(%ebx) jmp LDiv_exit LDiv_negative_result: movb SIGN_NEG,SIGN(%edi) LDiv_exit: leal -12(%ebp),%esp popl %ebx popl %edi popl %esi leave ret L_return_zero: movb TW_Zero,TAG(%edi) jmp LDiv_set_result_sign #ifdef PARANOID L_unknown_tags: push EX_INTERNAL | 0x208 call EXCEPTION /* Generate a NaN for unknown tags */ movl _CONST_QNaN,%eax movl %eax,(%edi) movl _CONST_QNaN+4,%eax movl %eax,SIGL(%edi) movl _CONST_QNaN+8,%eax movl %eax,SIGH(%edi) jmp LDiv_exit #endif PARANOID