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

• Lines: 257
• Date: Sat Feb 24 22:58:45 1996
• Orig file: v1.3.93/linux/arch/m68k/fpsp040/x_store.S
• Orig date: Thu Jan 1 02:00:00 1970

diff -u --recursive --new-file v1.3.93/linux/arch/m68k/fpsp040/x_store.S linux/arch/m68k/fpsp040/x_store.S
@@ -0,0 +1,256 @@
+|
+|	x_store.sa 3.2 1/24/91
+|
+|	store --- store operand to memory or register
+|
+|	Used by underflow and overflow handlers.
+|
+|	a6 = points to fp value to be stored.
+|
+
+|		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+|	THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF MOTOROLA 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_STORE:	|idnt    2,1 | Motorola 040 Floating Point Software Package
+
+	|section	8
+
+fpreg_mask:
+	.byte	0x80,0x40,0x20,0x10,0x08,0x04,0x02,0x01
+
+	.include "fpsp.h"
+
+	|xref	mem_write
+	|xref	get_fline
+	|xref	g_opcls
+	|xref	g_dfmtou
+	|xref	reg_dest
+
+	.global	dest_ext
+	.global	dest_dbl
+	.global	dest_sgl
+
+	.global	store
+store:
+	btstb	#E3,E_BYTE(%a6)
+	beqs	E1_sto
+E3_sto:
+	movel	CMDREG3B(%a6),%d0
+	bfextu	%d0{#6:#3},%d0		|isolate dest. reg from cmdreg3b
+sto_fp:
+	lea	fpreg_mask,%a1
+	moveb	(%a1,%d0.w),%d0		|convert reg# to dynamic register mask
+	tstb	LOCAL_SGN(%a0)
+	beqs	is_pos
+	bsetb	#sign_bit,LOCAL_EX(%a0)
+is_pos:
+	fmovemx (%a0),%d0		|move to correct register
+|
+|	if fp0-fp3 is being modified, we must put a copy
+|	in the USER_FPn variable on the stack because all exception
+|	handlers restore fp0-fp3 from there.
+|
+	cmpb	#0x80,%d0		
+	bnes	not_fp0
+	fmovemx %fp0-%fp0,USER_FP0(%a6)
+	rts
+not_fp0:
+	cmpb	#0x40,%d0
+	bnes	not_fp1
+	fmovemx %fp1-%fp1,USER_FP1(%a6)
+	rts
+not_fp1:
+	cmpb	#0x20,%d0
+	bnes	not_fp2
+	fmovemx %fp2-%fp2,USER_FP2(%a6)
+	rts
+not_fp2:
+	cmpb	#0x10,%d0
+	bnes	not_fp3
+	fmovemx %fp3-%fp3,USER_FP3(%a6)
+	rts
+not_fp3:
+	rts
+
+E1_sto:
+	bsrl	g_opcls		|returns opclass in d0
+	cmpib	#3,%d0
+	beq	opc011		|branch if opclass 3
+	movel	CMDREG1B(%a6),%d0
+	bfextu	%d0{#6:#3},%d0	|extract destination register
+	bras	sto_fp
+
+opc011:
+	bsrl	g_dfmtou	|returns dest format in d0
+|				;ext=00, sgl=01, dbl=10
+	movel	%a0,%a1		|save source addr in a1
+	movel	EXC_EA(%a6),%a0	|get the address
+	cmpil	#0,%d0		|if dest format is extended
+	beq	dest_ext	|then branch
+	cmpil	#1,%d0		|if dest format is single
+	beqs	dest_sgl	|then branch
+|
+|	fall through to dest_dbl
+|
+
+|
+|	dest_dbl --- write double precision value to user space
+|
+|Input
+|	a0 -> destination address
+|	a1 -> source in extended precision
+|Output
+|	a0 -> destroyed
+|	a1 -> destroyed
+|	d0 -> 0
+|
+|Changes extended precision to double precision.
+| Note: no attempt is made to round the extended value to double.
+|	dbl_sign = ext_sign
+|	dbl_exp = ext_exp - $3fff(ext bias) + $7ff(dbl bias)
+|	get rid of ext integer bit
+|	dbl_mant = ext_mant{62:12}
+|
+|	    	---------------   ---------------    ---------------
+|  extended ->  |s|    exp    |   |1| ms mant   |    | ls mant     |
+|	    	---------------   ---------------    ---------------
+|	   	 95	    64    63 62	      32      31     11	  0
+|				     |			     |
+|				     |			     |
+|				     |			     |
+|		 	             v   		     v
+|	    		      ---------------   ---------------
+|  double   ->  	      |s|exp| mant  |   |  mant       |
+|	    		      ---------------   ---------------
+|	   	 	      63     51   32   31	       0
+|
+dest_dbl:
+	clrl	%d0		|clear d0
+	movew	LOCAL_EX(%a1),%d0	|get exponent
+	subw	#0x3fff,%d0	|subtract extended precision bias
+	cmpw	#0x4000,%d0	|check if inf
+	beqs	inf		|if so, special case
+	addw	#0x3ff,%d0	|add double precision bias
+	swap	%d0		|d0 now in upper word
+	lsll	#4,%d0		|d0 now in proper place for dbl prec exp
+	tstb	LOCAL_SGN(%a1)	
+	beqs	get_mant	|if postive, go process mantissa
+	bsetl	#31,%d0		|if negative, put in sign information
+|				; before continuing
+	bras	get_mant	|go process mantissa
+inf:
+	movel	#0x7ff00000,%d0	|load dbl inf exponent
+	clrl	LOCAL_HI(%a1)	|clear msb
+	tstb	LOCAL_SGN(%a1)
+	beqs	dbl_inf		|if positive, go ahead and write it
+	bsetl	#31,%d0		|if negative put in sign information
+dbl_inf:
+	movel	%d0,LOCAL_EX(%a1)	|put the new exp back on the stack
+	bras	dbl_wrt
+get_mant:
+	movel	LOCAL_HI(%a1),%d1	|get ms mantissa
+	bfextu	%d1{#1:#20},%d1	|get upper 20 bits of ms
+	orl	%d1,%d0		|put these bits in ms word of double
+	movel	%d0,LOCAL_EX(%a1)	|put the new exp back on the stack
+	movel	LOCAL_HI(%a1),%d1	|get ms mantissa
+	movel	#21,%d0		|load shift count
+	lsll	%d0,%d1		|put lower 11 bits in upper bits
+	movel	%d1,LOCAL_HI(%a1)	|build lower lword in memory
+	movel	LOCAL_LO(%a1),%d1	|get ls mantissa
+	bfextu	%d1{#0:#21},%d0	|get ls 21 bits of double
+	orl	%d0,LOCAL_HI(%a1)	|put them in double result
+dbl_wrt:
+	movel	#0x8,%d0		|byte count for double precision number
+	exg	%a0,%a1		|a0=supervisor source, a1=user dest
+	bsrl	mem_write	|move the number to the user's memory
+	rts
+|
+|	dest_sgl --- write single precision value to user space
+|
+|Input
+|	a0 -> destination address
+|	a1 -> source in extended precision
+|
+|Output
+|	a0 -> destroyed
+|	a1 -> destroyed
+|	d0 -> 0
+|
+|Changes extended precision to single precision.
+|	sgl_sign = ext_sign
+|	sgl_exp = ext_exp - $3fff(ext bias) + $7f(sgl bias)
+|	get rid of ext integer bit
+|	sgl_mant = ext_mant{62:12}
+|
+|	    	---------------   ---------------    ---------------
+|  extended ->  |s|    exp    |   |1| ms mant   |    | ls mant     |
+|	    	---------------   ---------------    ---------------
+|	   	 95	    64    63 62	   40 32      31     12	  0
+|				     |	   |
+|				     |	   |
+|				     |	   |
+|		 	             v     v
+|	    		      ---------------
+|  single   ->  	      |s|exp| mant  |
+|	    		      ---------------
+|	   	 	      31     22     0
+|
+dest_sgl:
+	clrl	%d0
+	movew	LOCAL_EX(%a1),%d0	|get exponent
+	subw	#0x3fff,%d0	|subtract extended precision bias
+	cmpw	#0x4000,%d0	|check if inf
+	beqs	sinf		|if so, special case
+	addw	#0x7f,%d0		|add single precision bias
+	swap	%d0		|put exp in upper word of d0
+	lsll	#7,%d0		|shift it into single exp bits
+	tstb	LOCAL_SGN(%a1)	
+	beqs	get_sman	|if positive, continue
+	bsetl	#31,%d0		|if negative, put in sign first
+	bras	get_sman	|get mantissa
+sinf:
+	movel	#0x7f800000,%d0	|load single inf exp to d0
+	tstb	LOCAL_SGN(%a1)
+	beqs	sgl_wrt		|if positive, continue
+	bsetl	#31,%d0		|if negative, put in sign info
+	bras	sgl_wrt
+
+get_sman:
+	movel	LOCAL_HI(%a1),%d1	|get ms mantissa
+	bfextu	%d1{#1:#23},%d1	|get upper 23 bits of ms
+	orl	%d1,%d0		|put these bits in ms word of single
+
+sgl_wrt:
+	movel	%d0,L_SCR1(%a6)	|put the new exp back on the stack
+	movel	#0x4,%d0		|byte count for single precision number
+	tstl	%a0		|users destination address
+	beqs	sgl_Dn		|destination is a data register
+	exg	%a0,%a1		|a0=supervisor source, a1=user dest
+	leal	L_SCR1(%a6),%a0	|point a0 to data
+	bsrl	mem_write	|move the number to the user's memory
+	rts
+sgl_Dn:
+	bsrl	get_fline	|returns fline word in d0
+	andw	#0x7,%d0		|isolate register number
+	movel	%d0,%d1		|d1 has size:reg formatted for reg_dest
+	orl	#0x10,%d1		|reg_dest wants size added to reg#
+	bral	reg_dest	|size is X, rts in reg_dest will
+|				;return to caller of dest_sgl
+	
+dest_ext:
+	tstb	LOCAL_SGN(%a1)	|put back sign into exponent word
+	beqs	dstx_cont
+	bsetb	#sign_bit,LOCAL_EX(%a1)
+dstx_cont:
+	clrb	LOCAL_SGN(%a1)	|clear out the sign byte
+
+	movel	#0x0c,%d0		|byte count for extended number
+	exg	%a0,%a1		|a0=supervisor source, a1=user dest
+	bsrl	mem_write	|move the number to the user's memory
+	rts
+
+	|end