2fe8fb192f
There is important information about booting non-ack images in docs/UPDATING. ack/aout-format images can't be built any more, and booting clang/ELF-format ones is a little different. Updating to the new boot monitor is recommended. Changes in this commit: . drop boot monitor -> allowing dropping ack support . facility to copy ELF boot files to /boot so that old boot monitor can still boot fairly easily, see UPDATING . no more ack-format libraries -> single-case libraries . some cleanup of OBJECT_FMT, COMPILER_TYPE, etc cases . drop several ack toolchain commands, but not all support commands (e.g. aal is gone but acksize is not yet). . a few libc files moved to netbsd libc dir . new /bin/date as minix date used code in libc/ . test compile fix . harmonize includes . /usr/lib is no longer special: without ack, /usr/lib plays no kind of special bootstrapping role any more and bootstrapping is done exclusively through packages, so releases depend even less on the state of the machine making them now. . rename nbsd_lib* to lib* . reduce mtree
218 lines
5.9 KiB
ArmAsm
218 lines
5.9 KiB
ArmAsm
/* $NetBSD: ldexp.S,v 1.9 2009/12/14 01:07:42 matt Exp $ */
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/*-
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* Copyright (c) 1991, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Ralph Campbell.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <mips/asm.h>
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#if defined(LIBC_SCCS) && !defined(lint)
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#if 0
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RCSID("from: @(#)ldexp.s 8.1 (Berkeley) 6/4/93")
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#else
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RCSID("$NetBSD: ldexp.S,v 1.9 2009/12/14 01:07:42 matt Exp $")
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#endif
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#endif /* LIBC_SCCS and not lint */
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#define DEXP_INF 0x7ff
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#define DEXP_BIAS 1023
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#define DEXP_MIN -1022
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#define DEXP_MAX 1023
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#define DFRAC_BITS 52
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#define DIMPL_ONE 0x00100000
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#define DLEAD_ZEROS 31 - 20
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#define STICKYBIT 1
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#define GUARDBIT 0x80000000
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#define DSIGNAL_NAN 0x00040000
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#define DQUIET_NAN0 0x0007ffff
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#define DQUIET_NAN1 0xffffffff
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/*
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* double ldexp(x, N)
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* double x; int N;
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*
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* Return x * (2**N), for integer values N.
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*/
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LEAF(ldexp)
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mfc1 v1, $f13 # get MSW of x
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mfc1 t3, $f12 # get LSW of x
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sll t1, v1, 1 # get x exponent
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srl t1, t1, 32 - 11
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beq t1, DEXP_INF, 9f # is it a NAN or infinity?
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beq t1, zero, 1f # zero or denormalized number?
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addu t1, t1, a2 # scale exponent
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sll v0, a2, 20 # position N for addition
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bge t1, DEXP_INF, 8f # overflow?
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addu v0, v0, v1 # multiply by (2**N)
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ble t1, zero, 4f # underflow?
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mtc1 v0, $f1 # save MSW of result
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mtc1 t3, $f0 # save LSW of result
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j ra
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1:
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sll t2, v1, 32 - 20 # get x fraction
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srl t2, t2, 32 - 20
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srl t0, v1, 31 # get x sign
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bne t2, zero, 1f
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beq t3, zero, 9f # result is zero
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1:
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/*
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* Find out how many leading zero bits are in t2,t3 and put in t9.
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*/
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move v0, t2
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move t9, zero
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bne t2, zero, 1f
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move v0, t3
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addu t9, 32
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1:
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srl ta0, v0, 16
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bne ta0, zero, 1f
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addu t9, 16
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sll v0, 16
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1:
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srl ta0, v0, 24
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bne ta0, zero, 1f
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addu t9, 8
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sll v0, 8
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1:
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srl ta0, v0, 28
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bne ta0, zero, 1f
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addu t9, 4
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sll v0, 4
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1:
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srl ta0, v0, 30
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bne ta0, zero, 1f
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addu t9, 2
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sll v0, 2
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1:
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srl ta0, v0, 31
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bne ta0, zero, 1f
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addu t9, 1
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/*
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* Now shift t2,t3 the correct number of bits.
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*/
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1:
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subu t9, t9, DLEAD_ZEROS # dont count normal leading zeros
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li t1, DEXP_MIN + DEXP_BIAS
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subu t1, t1, t9 # adjust exponent
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addu t1, t1, a2 # scale exponent
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li v0, 32
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blt t9, v0, 1f
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subu t9, t9, v0 # shift fraction left >= 32 bits
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sll t2, t3, t9
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move t3, zero
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b 2f
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1:
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subu v0, v0, t9 # shift fraction left < 32 bits
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sll t2, t2, t9
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srl ta0, t3, v0
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or t2, t2, ta0
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sll t3, t3, t9
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2:
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bge t1, DEXP_INF, 8f # overflow?
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ble t1, zero, 4f # underflow?
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sll t2, t2, 32 - 20 # clear implied one bit
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srl t2, t2, 32 - 20
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3:
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sll t1, t1, 31 - 11 # reposition exponent
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sll t0, t0, 31 # reposition sign
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or t0, t0, t1 # put result back together
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or t0, t0, t2
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mtc1 t0, $f1 # save MSW of result
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mtc1 t3, $f0 # save LSW of result
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j ra
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4:
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li v0, 0x80000000
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ble t1, -52, 7f # is result too small for denorm?
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sll t2, v1, 31 - 20 # clear exponent, extract fraction
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or t2, t2, v0 # set implied one bit
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blt t1, -30, 2f # will all bits in t3 be shifted out?
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srl t2, t2, 31 - 20 # shift fraction back to normal position
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subu t1, t1, 1
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sll ta0, t2, t1 # shift right t2,t3 based on exponent
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srl t8, t3, t1 # save bits shifted out
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negu t1
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srl t3, t3, t1
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or t3, t3, ta0
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srl t2, t2, t1
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bge t8, zero, 1f # does result need to be rounded?
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addu t3, t3, 1 # round result
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sltu ta0, t3, 1
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sll t8, t8, 1
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addu t2, t2, ta0
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bne t8, zero, 1f # round result to nearest
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and t3, t3, ~1
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1:
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mtc1 t3, $f0 # save denormalized result (LSW)
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mtc1 t2, $f1 # save denormalized result (MSW)
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bge v1, zero, 1f # should result be negative?
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neg.d $f0, $f0 # negate result
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1:
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j ra
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2:
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mtc1 zero, $f1 # exponent and upper fraction
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addu t1, t1, 20 # compute amount to shift right by
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sll t8, t2, t1 # save bits shifted out
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negu t1
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srl t3, t2, t1
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bge t8, zero, 1f # does result need to be rounded?
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addu t3, t3, 1 # round result
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sltu ta0, t3, 1
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sll t8, t8, 1
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mtc1 ta0, $f1 # exponent and upper fraction
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bne t8, zero, 1f # round result to nearest
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and t3, t3, ~1
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1:
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mtc1 t3, $f0
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bge v1, zero, 1f # is result negative?
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neg.d $f0, $f0 # negate result
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1:
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j ra
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7:
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mtc1 zero, $f0 # result is zero
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mtc1 zero, $f1
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beq t0, zero, 1f # is result positive?
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neg.d $f0, $f0 # negate result
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1:
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j ra
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8:
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li t1, 0x7ff00000 # result is infinity (MSW)
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mtc1 t1, $f1
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mtc1 zero, $f0 # result is infinity (LSW)
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bge v1, zero, 1f # should result be negative infinity?
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neg.d $f0, $f0 # result is negative infinity
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1:
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add.d $f0, $f0 # cause overflow faults if enabled
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j ra
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9:
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mov.d $f0, $f12 # yes, result is just x
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j ra
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END(ldexp)
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