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NetWinder Floating Point Emulator
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(c) Rebel.com, 1998-1999
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Direct questions, comments to Scott Bambrough <scottb@netwinder.org>
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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The FPSR is a 32 bit register consisting of 4 parts, each exactly
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EXCEPTION TRAP ENABLE BYTE
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CUMULATIVE EXCEPTION FLAGS BYTE
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The FPCR is a 32 bit register consisting of bit flags.
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Note: the system id byte is read only */
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typedef unsigned int FPSR; /* type for floating point status register */
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typedef unsigned int FPCR; /* type for floating point control register */
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#define MASK_SYSID 0xff000000
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#define BIT_HARDWARE 0x80000000
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#define FP_EMULATOR 0x01000000 /* System ID for emulator */
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#define FP_ACCELERATOR 0x81000000 /* System ID for FPA11 */
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/* EXCEPTION TRAP ENABLE BYTE
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----------------------------- */
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#define MASK_TRAP_ENABLE 0x00ff0000
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#define MASK_TRAP_ENABLE_STRICT 0x001f0000
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#define BIT_IXE 0x00100000 /* inexact exception enable */
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#define BIT_UFE 0x00080000 /* underflow exception enable */
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#define BIT_OFE 0x00040000 /* overflow exception enable */
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#define BIT_DZE 0x00020000 /* divide by zero exception enable */
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#define BIT_IOE 0x00010000 /* invalid operation exception enable */
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/* SYSTEM CONTROL BYTE
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---------------------- */
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#define MASK_SYSTEM_CONTROL 0x0000ff00
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#define MASK_TRAP_STRICT 0x00001f00
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#define BIT_AC 0x00001000 /* use alternative C-flag definition
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#define BIT_EP 0x00000800 /* use expanded packed decimal format */
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#define BIT_SO 0x00000400 /* select synchronous operation of FPA */
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#define BIT_NE 0x00000200 /* NaN exception bit */
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#define BIT_ND 0x00000100 /* no denormalized numbers bit */
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/* CUMULATIVE EXCEPTION FLAGS BYTE
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---------------------------------- */
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#define MASK_EXCEPTION_FLAGS 0x000000ff
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#define MASK_EXCEPTION_FLAGS_STRICT 0x0000001f
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#define BIT_IXC 0x00000010 /* inexact exception flag */
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#define BIT_UFC 0x00000008 /* underflow exception flag */
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#define BIT_OFC 0x00000004 /* overfloat exception flag */
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#define BIT_DZC 0x00000002 /* divide by zero exception flag */
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#define BIT_IOC 0x00000001 /* invalid operation exception flag */
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/* Floating Point Control Register
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----------------------------------*/
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#define BIT_RU 0x80000000 /* rounded up bit */
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#define BIT_IE 0x10000000 /* inexact bit */
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#define BIT_MO 0x08000000 /* mantissa overflow bit */
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#define BIT_EO 0x04000000 /* exponent overflow bit */
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#define BIT_SB 0x00000800 /* store bounce */
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#define BIT_AB 0x00000400 /* arithmetic bounce */
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#define BIT_RE 0x00000200 /* rounding exception */
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#define BIT_DA 0x00000100 /* disable FPA */
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#define MASK_OP 0x00f08010 /* AU operation code */
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#define MASK_PR 0x00080080 /* AU precision */
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#define MASK_S1 0x00070000 /* AU source register 1 */
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#define MASK_S2 0x00000007 /* AU source register 2 */
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#define MASK_DS 0x00007000 /* AU destination register */
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#define MASK_RM 0x00000060 /* AU rounding mode */
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#define MASK_ALU 0x9cfff2ff /* only ALU can write these bits */
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#define MASK_RESET 0x00000d00 /* bits set on reset, all others cleared */
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#define MASK_WFC MASK_RESET
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#define MASK_RFC ~MASK_RESET