patch-1.3.94 linux/arch/m68k/fpsp040/x_snan.S

• Lines: 278
• Date: Sat Feb 24 22:58:45 1996
• Orig file: v1.3.93/linux/arch/m68k/fpsp040/x_snan.S
• Orig date: Thu Jan 1 02:00:00 1970

diff -u --recursive --new-file v1.3.93/linux/arch/m68k/fpsp040/x_snan.S linux/arch/m68k/fpsp040/x_snan.S
@@ -0,0 +1,277 @@
+|
+|	x_snan.sa 3.3 7/1/91
+|
+| fpsp_snan --- FPSP handler for signalling NAN exception
+|
+| SNAN for float -> integer conversions (integer conversion of
+| an SNAN) is a non-maskable run-time exception.
+|
+| For trap disabled the 040 does the following:
+| If the dest data format is s, d, or x, then the SNAN bit in the NAN
+| is set to one and the resulting non-signaling NAN (truncated if
+| necessary) is transferred to the dest.  If the dest format is b, w,
+| or l, then garbage is written to the dest (actually the upper 32 bits
+| of the mantissa are sent to the integer unit).
+|
+| For trap enabled the 040 does the following:
+| If the inst is move_out, then the results are the same as for trap 
+| disabled with the exception posted.  If the instruction is not move_
+| out, the dest. is not modified, and the exception is posted.
+|
+
+|		Copyright (C) Motorola, Inc. 1990
+|			All Rights Reserved
+|
+|	THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF MOTOROLA 
+|	The copyright notice above does not evidence any  
+|	actual or intended publication of such source code.
+
+X_SNAN:	|idnt    2,1 | Motorola 040 Floating Point Software Package
+
+	|section	8
+
+	.include "fpsp.h"
+
+	|xref	get_fline
+	|xref	mem_write
+	|xref	real_snan
+	|xref	real_inex
+	|xref	fpsp_done
+	|xref	reg_dest
+
+	.global	fpsp_snan
+fpsp_snan:
+	link		%a6,#-LOCAL_SIZE
+	fsave		-(%a7)
+	moveml		%d0-%d1/%a0-%a1,USER_DA(%a6)
+	fmovemx	%fp0-%fp3,USER_FP0(%a6)
+	fmoveml	%fpcr/%fpsr/%fpiar,USER_FPCR(%a6)
+
+|
+| Check if trap enabled
+|
+	btstb		#snan_bit,FPCR_ENABLE(%a6)
+	bnes		ena		|If enabled, then branch
+
+	bsrl		move_out	|else SNAN disabled
+|
+| It is possible to have an inex1 exception with the
+| snan.  If the inex enable bit is set in the FPCR, and either
+| inex2 or inex1 occured, we must clean up and branch to the
+| real inex handler.
+|
+ck_inex:
+	moveb	FPCR_ENABLE(%a6),%d0
+	andb	FPSR_EXCEPT(%a6),%d0
+	andib	#0x3,%d0
+	beq	end_snan
+|
+| Inexact enabled and reported, and we must take an inexact exception.
+|
+take_inex:
+	moveb		#INEX_VEC,EXC_VEC+1(%a6)
+	moveml		USER_DA(%a6),%d0-%d1/%a0-%a1
+	fmovemx	USER_FP0(%a6),%fp0-%fp3
+	fmoveml	USER_FPCR(%a6),%fpcr/%fpsr/%fpiar
+	frestore	(%a7)+
+	unlk		%a6
+	bral		real_inex
+|
+| SNAN is enabled.  Check if inst is move_out.
+| Make any corrections to the 040 output as necessary.
+|
+ena:
+	btstb		#5,CMDREG1B(%a6) |if set, inst is move out
+	beq		not_out
+
+	bsrl		move_out
+
+report_snan:
+	moveb		(%a7),VER_TMP(%a6)
+	cmpib		#VER_40,(%a7)	|test for orig unimp frame
+	bnes		ck_rev
+	moveql		#13,%d0		|need to zero 14 lwords
+	bras		rep_con
+ck_rev:
+	moveql		#11,%d0		|need to zero 12 lwords
+rep_con:
+	clrl		(%a7)
+loop1:
+	clrl		-(%a7)		|clear and dec a7
+	dbra		%d0,loop1
+	moveb		VER_TMP(%a6),(%a7) |format a busy frame
+	moveb		#BUSY_SIZE-4,1(%a7)
+	movel		USER_FPSR(%a6),FPSR_SHADOW(%a6)
+	orl		#sx_mask,E_BYTE(%a6)
+	moveml		USER_DA(%a6),%d0-%d1/%a0-%a1
+	fmovemx	USER_FP0(%a6),%fp0-%fp3
+	fmoveml	USER_FPCR(%a6),%fpcr/%fpsr/%fpiar
+	frestore	(%a7)+
+	unlk		%a6
+	bral		real_snan
+|
+| Exit snan handler by expanding the unimp frame into a busy frame
+|
+end_snan:
+	bclrb		#E1,E_BYTE(%a6)
+
+	moveb		(%a7),VER_TMP(%a6)
+	cmpib		#VER_40,(%a7)	|test for orig unimp frame
+	bnes		ck_rev2
+	moveql		#13,%d0		|need to zero 14 lwords
+	bras		rep_con2
+ck_rev2:
+	moveql		#11,%d0		|need to zero 12 lwords
+rep_con2:
+	clrl		(%a7)
+loop2:
+	clrl		-(%a7)		|clear and dec a7
+	dbra		%d0,loop2
+	moveb		VER_TMP(%a6),(%a7) |format a busy frame
+	moveb		#BUSY_SIZE-4,1(%a7) |write busy size
+	movel		USER_FPSR(%a6),FPSR_SHADOW(%a6)
+	orl		#sx_mask,E_BYTE(%a6)
+	moveml		USER_DA(%a6),%d0-%d1/%a0-%a1
+	fmovemx	USER_FP0(%a6),%fp0-%fp3
+	fmoveml	USER_FPCR(%a6),%fpcr/%fpsr/%fpiar
+	frestore	(%a7)+
+	unlk		%a6
+	bral		fpsp_done
+
+|
+| Move_out 
+|
+move_out:
+	movel		EXC_EA(%a6),%a0	|get <ea> from exc frame
+
+	bfextu		CMDREG1B(%a6){#3:#3},%d0 |move rx field to d0{2:0}
+	cmpil		#0,%d0		|check for long
+	beqs		sto_long	|branch if move_out long
+	
+	cmpil		#4,%d0		|check for word
+	beqs		sto_word	|branch if move_out word
+	
+	cmpil		#6,%d0		|check for byte
+	beqs		sto_byte	|branch if move_out byte
+	
+|
+| Not byte, word or long
+|
+	rts
+|	
+| Get the 32 most significant bits of etemp mantissa
+|
+sto_long:
+	movel		ETEMP_HI(%a6),%d1
+	movel		#4,%d0		|load byte count
+|
+| Set signalling nan bit
+|
+	bsetl		#30,%d1			
+|
+| Store to the users destination address
+|
+	tstl		%a0		|check if <ea> is 0
+	beqs		wrt_dn		|destination is a data register
+	
+	movel		%d1,-(%a7)	|move the snan onto the stack
+	movel		%a0,%a1		|load dest addr into a1
+	movel		%a7,%a0		|load src addr of snan into a0
+	bsrl		mem_write	|write snan to user memory
+	movel		(%a7)+,%d1	|clear off stack
+	rts
+|
+| Get the 16 most significant bits of etemp mantissa
+|
+sto_word:
+	movel		ETEMP_HI(%a6),%d1
+	movel		#2,%d0		|load byte count
+|
+| Set signalling nan bit
+|
+	bsetl		#30,%d1			
+|
+| Store to the users destination address
+|
+	tstl		%a0		|check if <ea> is 0
+	beqs		wrt_dn		|destination is a data register
+
+	movel		%d1,-(%a7)	|move the snan onto the stack
+	movel		%a0,%a1		|load dest addr into a1
+	movel		%a7,%a0		|point to low word
+	bsrl		mem_write	|write snan to user memory
+	movel		(%a7)+,%d1	|clear off stack
+	rts
+|
+| Get the 8 most significant bits of etemp mantissa
+|
+sto_byte:
+	movel		ETEMP_HI(%a6),%d1
+	movel		#1,%d0		|load byte count
+|
+| Set signalling nan bit
+|
+	bsetl		#30,%d1			
+|
+| Store to the users destination address
+|
+	tstl		%a0		|check if <ea> is 0
+	beqs		wrt_dn		|destination is a data register
+	movel		%d1,-(%a7)	|move the snan onto the stack
+	movel		%a0,%a1		|load dest addr into a1
+	movel		%a7,%a0		|point to source byte
+	bsrl		mem_write	|write snan to user memory
+	movel		(%a7)+,%d1	|clear off stack
+	rts
+
+|
+|	wrt_dn --- write to a data register
+|
+|	We get here with D1 containing the data to write and D0 the
+|	number of bytes to write: 1=byte,2=word,4=long.
+|
+wrt_dn:
+	movel		%d1,L_SCR1(%a6)	|data
+	movel		%d0,-(%a7)	|size
+	bsrl		get_fline	|returns fline word in d0
+	movel		%d0,%d1
+	andil		#0x7,%d1		|d1 now holds register number
+	movel		(%sp)+,%d0	|get original size
+	cmpil		#4,%d0
+	beqs		wrt_long
+	cmpil		#2,%d0
+	bnes		wrt_byte
+wrt_word:
+	orl		#0x8,%d1
+	bral		reg_dest
+wrt_long:
+	orl		#0x10,%d1
+	bral		reg_dest
+wrt_byte:
+	bral		reg_dest
+|
+| Check if it is a src nan or dst nan
+|
+not_out:
+	movel		DTAG(%a6),%d0	
+	bfextu		%d0{#0:#3},%d0	|isolate dtag in lsbs
+
+	cmpib		#3,%d0		|check for nan in destination
+	bnes		issrc		|destination nan has priority
+dst_nan:
+	btstb		#6,FPTEMP_HI(%a6) |check if dest nan is an snan
+	bnes		issrc		|no, so check source for snan
+	movew		FPTEMP_EX(%a6),%d0
+	bras		cont
+issrc:
+	movew		ETEMP_EX(%a6),%d0
+cont:
+	btstl		#15,%d0		|test for sign of snan
+	beqs		clr_neg
+	bsetb		#neg_bit,FPSR_CC(%a6)
+	bra		report_snan
+clr_neg:
+	bclrb		#neg_bit,FPSR_CC(%a6)
+	bra		report_snan
+
+	|end