vaxfloat.s

<B>Digital的Unix操作系统VAX 4.2源码</B>

/*	@(#)vaxfloat.s	4.1		7/2/90		*/

# include "../machine/emul/vaxemul.h"
# include "../machine/psl.h"
# include "../machine/emul/vaxregdef.h"



/************************************************************************
 *									*
 *			Copyright (c) 1984 by				*
 *		Digital Equipment Corporation, Maynard, MA		*
 *			All rights reserved.				*
 *									*
 *   This software is furnished under a license and may be used and	*
 *   copied  only  in accordance with the terms of such license and	*
 *   with the  inclusion  of  the  above  copyright  notice.   This	*
 *   software  or  any  other copies thereof may not be provided or	*
 *   otherwise made available to any other person.  No title to and	*
 *   ownership of the software is hereby transferred.			*
 *									*
 *   The information in this software is subject to change  without	*
 *   notice  and should not be construed as a commitment by Digital	*
 *   Equipment Corporation.						*
 *									*
 *   Digital assumes no responsibility for the use  or  reliability	*
 *   of its software on equipment which is not supplied by Digital.	*
 *									*
 ************************************************************************/

/************************************************************************
 *
 *			Modification History
 *
 * 	jaw,	12-jun-89
 *	fix branch in iteration of polyf...also pick up fix for extra
 *	percision in poly{fdg}.
 *
 *	Stephen Reilly, 05-Dec-84
 * 003- Fixed typo that made floating operations  work incorrectly.
 *
 *	Stephen Reilly, 28-Aug-84
 * 002- The polyf routine failed to clear r1.  I received this bug
 *	from Jeff Wiener on 21-Aug-1984.
 *
 *	Stephen Reilly, 28-Aug-84
 * 001- Corrected a BBS instruction in MULTIPLY__FFLOAT.  It has referred
 *	to FRACTION+8(FP).  It should have been FRACTION+12(FP). I 
 *	received this fix from Jeff Wiener.  The date he fixed it was
 *	10-Aug-1984.
 *
 *	Stephen Reilly, 20-Mar-84
 * 000- This code is the modification of the VMS emulation codethat 
 *	was written by Derek Zave.  It has been modified to run
 *	on Ultrix.
 *
 ***********************************************************************/

 #++
 # facility: vms executive floating point emulation
 #
 # abstract:
 #
 #	loadable code that emulates f, d, g and h floating instructions on
 #	any processor.  octaword integer emulation is included.
 #
 # environment: runs at any access mode, ast reentrant
 #
 # author: steven b. lionel, 22-march-1983
 #
 #	emulation code based on lib$emulate by derek zave.
 #
 # modified by:
 #
 #	LJK0025		Lawrence J. Kenah	8-Mar-1984
 #	Change PRVMOD field in PSL that is in effect while emulator is
 #	executing so that PROBEs work with correct access mode when the
 #	emulator is used in exec or supervisor mode. Fix incorrect
 #	register usage in READ_FAULT.
 #
 #	LJK0015		Lawrence J. Kenah	2-Feb-1984
 #	Fix error destinations for inaccessible instruction stream or 
 #	exception stack. Use G^ addressing for SYS.STB symbols.
 #
 #	JCW1005		Jeffrey C. Wiener	11-January-1984
 #	Corrected the discription of the algorithm used to divide unsigned
 #	multiple length integers. A fix was also added to the associated
 #	code to fix an outstanding DIVG/DIVH bug. The fix checks a "carry-
 #	over". If the "carry-over" is negative, then the "carry-over" is
 #	zeroed.
 #
 #	sbl1002		steven b. lionel	23-may-1983
 #	add check for no p1 region.
 #
 #	sbl1001		steven b. lionel	22-march-1983
 #	adapt lib$emulate for integration into the vms executive.
 #--

 #
 # macros:
 #
 
 #	macro for comparing condition codes
 # 	.macro	cmpcond	cond,loc
 #	cmpzv	#3,#26,loc,#cond@-3
 #	.endm
 
 #	macro for loading op_types with the types of the various operands,
 #	.macro	set_op_types	op1=f,op2=f,op3=f,op4=f,op5=f,op6=f
 #	.narg	n_args
 #	.if	eq n_args-6	# 6 arguments?
 #	movw	#<typ_'op5'+<typ_'op6'@8>>, op_types4(fp)
 #	.ndc
 #	.if	eq n_args-5	# 5 arguments?
 #	movb	#<typ_'op5'>, op_types4(fp)
 # 	.endc
 #	.if	gt n_args-2	# more than 2 arguments?
 #	movl	#<typ_'op1'+ -
 #		 <typ_'op2'@8>+ -
 #		 <typ_'op3'@16>+ -
 #		 <typ_'op4'@24>>, op_types(fp)
 #	.endc
 #	.if	eq n_args-2	# 2 arguments?
 #	movw	#<typ_'op1'+<typ_'op2'@8>>, op_types(fp)
 #	.endc
 #	.if	eq n_args-1	# 1 argument?
 #	movb	#typ_'op1', op_types(fp)
 #	.endc
 #	.endm
 
 #
 # equated symbols:
 #
 #	see body of routine

 #
 # own storage:
 #
 #	none
 #

 #	****************************************************************
 #	*							       *
 #	*							       *
 #	*			assorted definitions		       *
 #	*							       *
 #	*							       *
 #	****************************************************************
 #
 #
 #
 #	parameters
 #
# define  call_args 40
				# flexible stack space (longwords)
 #
 #	opcode range limits
 #
# define  lo_1byte 0x40
# define  hi_1byte 0x76
# define lo_2byte 0x32
# define hi_2byte 0xff
 #
 #	operand area layout
 #
# define zero 0
					# zero indicator (byte)
# define sign 1			
					# sign indicator (byte)
# define power 4				
					# exponent (longword)
# define fraction 8			
					# fraction area (octaword)
# define operand_size 24
					# operand area size (bytes)
 #
 #	bits in the processor status longword (psl)
 #
# define psl_c 0			
					# carry indicator
# define psl_v 1			
					# overflow indicator
# define psl_z 2			
					# zero indicator
# define psl_n 3	
					# negative indicator
# define psl_t 4			
					# trace enable indicator
# define psl_iv	5			
					# integer overflow trap enable
# define psl_fu	6
					# floating underflow fault enable
# define psl_cam 24
					# low bit of current access mode
# define psl_fpd 27			
					# instruction first part done
# define psl_tp	30
					# trace pending indicator
 #
 #	masks for the processor status longword
 #
# define pslm_c	1<<psl_c 		
					# carry indicator
# define pslm_v 1<<psl_v 		
					# overflow indicator
# define pslm_z 1<<psl_z 		
					# zero indicator
# define pslm_n	1<<psl_n 		
					# negative indicator
# define pslm_vc pslm_v + pslm_c
					# overflow and carry indicators
# define pslm_nzvc pslm_vc + pslm_n+pslm_z
					# condition code
# define pslm_nz pslm_n +  pslm_z
					# comparison codes
# define pslm_nzv pslm_nz + pslm_v
					# bits other than carry
# define pslm_lss  pslm_n
					# less than condition code
# define pslm_eql pslm_z
					# equals condition code
# define pslm_gtr 0
					# greater than condition code
 #
 #	call frame layout

 #
# define handler 0
					# condition handler location
# define save_psw 4
					# saved processor status word
# define save_mask 6
					# register save mask
# define mask_align 14
					# bit position of alignment bits
# define save_ap 8
					# user's argument pointer
# define save_fp 12
					# user's frame pointer
# define save_pc 16
					# return point
# define reg_r0	20
					# user's r0
# define reg_r1	24
					# user's r1
# define reg_r2	28
					# user's r2
# define reg_r3	32
					# user's r3
# define reg_r4	36
					# user's r4
# define reg_r5	40
					# user's r5
# define reg_r6	44
					# user's r6
# define reg_r7	48
					# user's r7
# define reg_r8	52
					# user's r8
# define reg_r9	56
					# user's r9
# define reg_r10 60
					# user's r10
# define reg_r11 64
					# user's r11
# define frame_end 68
					# end of call frame
 #
 #	call frame extension layout
 #
# define reg_ap	68
					# user's ap
# define reg_fp	72
					# user's fp
# define reg_sp	76
					# user's sp
# define reg_pc	80
					# user's pc
# define psl 84
					# user's psl
# define local_end 88
					# end of emulator local storage
# define temp 88
					# temporary area for arithmetic
 #
 #	local storage layout
 #
# define save_align -1
					# saved copy of alignment bits
# define save_parcnt -2
					# saved copy of parameter count
# define mode -3
					# access mode for probes
# define flags -4
					# indicator flag bits
# define short_local -5
					# start of short local storage
# define regmod_pc -6
					# changes to user's pc
# define regmod_sp -7
					# changes to user's sp
# define regmod_fp -8
					# changes to user's fp
# define regmod_ap -9
					# changes to user's ap
# define regmod_r11 -10
					# changes to user's r11
# define regmod_r10 -11
					# changes to user's r10
# define regmod_r9 -12
					# changes to user's r9
# define regmod_r8 -13
					# changes to user's r8
# define regmod_r7 -14
					# changes to user's r7
# define regmod_r6 -15
					# changes to user's r6
# define regmod_r5 -16
					# changes to user's r5
# define regmod_r4 -17
					# changes to user's r4
# define regmod_r3 -18
					# changes to user's r3
# define regmod_r2  -19
					# changes to user's r2
# define regmod_r1 -20
					# changes to user's r1
# define regmod_r0 -21
					# changes to user's r0
# define address1 -25
					# temporary address area #1
# define address2 -29
					# temporary address area #2

# define address3 -33
					# temporary address area #3
# define operand1 address3 - operand_size
					# temporary operand area #1
# define operand2 operand1 - operand_size
					# temporary operand area #2
# define operand3 operand2 - operand_size	
					# temporary operand area #3
# define op_types4 operand3 - 4
					# four bytes for operand type codes
# define op_types op_types4 - 4
					# four more bytes for operand type codes
# define op_index op_types - 4
#define poly_x_flag op_index-1
					# pointer to current byte of op_types
# define local_start  poly_x_flag

			# op_index start of emulator local storage
 #
 #	indicator bit numbers
 #	
# define flag0	0
					# inhibit local store check
# define flag1	1
					# register mode operand
# define flag2	2
					# (not assigned)
# define flag3	3
					# (not assigned)
# define flag4  4
					# (not assigned)
# define flag5	5
					# (not assigned)
# define flag6	6
					# (not assigned)
# define flag7	7
					# temporary use
 #
 #	indicator bit masks
 #
# define flag0m	1<<0
					# inhibit local store check
# define flag1m	1<<1
					# register mode operand
# define flag2m 1<<2
					# (not assigned)
# define flag3m 1<<3
					# (not assigned)
# define flag4m	1<<4
					# (not assigned)
# define flag5m	1<<5
					# (not assigned)
# define flag6m	1<<6
					# (not assigned)
# define flag7m	1<<7
					# temporary use
 #
 #	fields in the operand areas
 #
# define zero1	operand1 + zero
					# zero flag of operand1
# define zero2	operand2 + zero
					# zero flag of operand2
# define zero3	operand3 + zero
					# zero flag of operand3
# define sign1	operand1 + sign
					# sign of operand1
# define sign2	operand2 + sign
					# sign of operand2
# define sign3	operand3 + sign
					# sign of operand3
# define power1	operand1 + power
					# exponent of operand1
# define power2	operand2 + power
					# exponent of operand2
# define power3	operand3 + power
					# exponent of operand3
# define fraction1 operand1 + fraction
					# fraction of operand1
# define fraction2 operand2 + fraction
					# fraction of operand2
# define fraction3 operand3 + fraction
					# fraction of operand3
 #
 #	access type code definitions
 #
# define type_read 1
					# read only access
# define type_write 2
					# write only access
# define type_modify 3
					# modify access
# define type_address 4