25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis/*
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * CDDL HEADER START
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis *
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * The contents of this file are subject to the terms of the
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * Common Development and Distribution License (the "License").
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * You may not use this file except in compliance with the License.
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis *
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * or http://www.opensolaris.org/os/licensing.
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * See the License for the specific language governing permissions
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * and limitations under the License.
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis *
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * When distributing Covered Code, include this CDDL HEADER in each
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
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25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * fields enclosed by brackets "[]" replaced with your own identifying
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * information: Portions Copyright [yyyy] [name of copyright owner]
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis *
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * CDDL HEADER END
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis */
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis/*
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * Copyright 2011 Nexenta Systems, Inc. All rights reserved.
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis */
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis/*
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * Use is subject to license terms.
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis */
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis .file "ilogb.s"
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis#include "libm.h"
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr JasiukajtisLIBM_ANSI_PRAGMA_WEAK(ilogb,function)
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis#include "xpg6.h"
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis .data
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis .align 8
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtistwo52: .long 0x0,0x43300000 / 2**52
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis ENTRY(ilogb)
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis movl 8(%esp),%eax / eax <-- hi_32(x)
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis andl $0x7fffffff,%eax / eax <-- hi_32(abs(x))
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis testl $0x7ff00000,%eax / is bexp(x) 0?
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis jz .bexp_0 / jump if x is 0 or subnormal
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis / biased exponent is non-zero
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis cmpl $0x7ff00000,%eax / is bexp(x) 0x7ff?
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis jae .bexp_all_1 / jump if x is NaN or Inf
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis shrl $20,%eax / eax <-- bexp(x)
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis subl $1023,%eax / unbias exponent by 1023
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis ret
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis.bexp_all_1:
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis movl $0x7fffffff,%eax / x is NaN or inf, so return 0x7fffffff
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis jmp 0f
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis.bexp_0:
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis orl 4(%esp),%eax / test whether x is 0
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis jnz .ilogb_subnorm
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis movl $0x80000001,%eax / x is +/-0, so return 0x80000001
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis0:
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis PIC_SETUP(0)
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis PIC_G_LOAD(movzwl,__xpg6,ecx)
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis PIC_WRAPUP
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis andl $_C99SUSv3_ilogb_0InfNaN_raises_invalid,%ecx
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis cmpl $0,%ecx
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis je 1f
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis fldz
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis fdivp %st,%st(0) / raise invalid as per SUSv3
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis1:
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis ret
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis.ilogb_subnorm: / subnormal input
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis fldl 4(%esp) / push x
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis PIC_SETUP(1)
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis fmull PIC_L(two52) / x*2**52
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis PIC_WRAPUP
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis subl $8,%esp / set up storage area
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis fstpl (%esp) / store x*2**52 in storage are
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis movl $0x7ff00000,%eax
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis andl 4(%esp),%eax
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis shrl $20,%eax / extract exponent of x*2**52
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis subl $1075,%eax / unbias it by 1075 (= 1023 + 52)
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis addl $8,%esp
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis ret
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis .align 4
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis SET_SIZE(ilogb)