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

• Lines: 141
• Date: Sat Feb 24 22:58:42 1996
• Orig file: v1.3.93/linux/arch/m68k/fpsp040/binstr.S
• Orig date: Thu Jan 1 02:00:00 1970

diff -u --recursive --new-file v1.3.93/linux/arch/m68k/fpsp040/binstr.S linux/arch/m68k/fpsp040/binstr.S
@@ -0,0 +1,140 @@
+|
+|	binstr.sa 3.3 12/19/90
+|
+|
+|	Description: Converts a 64-bit binary integer to bcd.
+|
+|	Input: 64-bit binary integer in d2:d3, desired length (LEN) in
+|          d0, and a  pointer to start in memory for bcd characters
+|          in d0. (This pointer must point to byte 4 of the first
+|          lword of the packed decimal memory string.)
+|
+|	Output:	LEN bcd digits representing the 64-bit integer.
+|
+|	Algorithm:
+|		The 64-bit binary is assumed to have a decimal point before
+|		bit 63.  The fraction is multiplied by 10 using a mul by 2
+|		shift and a mul by 8 shift.  The bits shifted out of the
+|		msb form a decimal digit.  This process is iterated until
+|		LEN digits are formed.
+|
+|	A1. Init d7 to 1.  D7 is the byte digit counter, and if 1, the
+|		digit formed will be assumed the least significant.  This is
+|		to force the first byte formed to have a 0 in the upper 4 bits.
+|
+|	A2. Beginning of the loop:
+|		Copy the fraction in d2:d3 to d4:d5.
+|
+|	A3. Multiply the fraction in d2:d3 by 8 using bit-field
+|		extracts and shifts.  The three msbs from d2 will go into
+|		d1.
+|
+|	A4. Multiply the fraction in d4:d5 by 2 using shifts.  The msb
+|		will be collected by the carry.
+|
+|	A5. Add using the carry the 64-bit quantities in d2:d3 and d4:d5
+|		into d2:d3.  D1 will contain the bcd digit formed.
+|
+|	A6. Test d7.  If zero, the digit formed is the ms digit.  If non-
+|		zero, it is the ls digit.  Put the digit in its place in the
+|		upper word of d0.  If it is the ls digit, write the word
+|		from d0 to memory.
+|
+|	A7. Decrement d6 (LEN counter) and repeat the loop until zero.
+|
+|	Implementation Notes:
+|
+|	The registers are used as follows:
+|
+|		d0: LEN counter
+|		d1: temp used to form the digit
+|		d2: upper 32-bits of fraction for mul by 8
+|		d3: lower 32-bits of fraction for mul by 8
+|		d4: upper 32-bits of fraction for mul by 2
+|		d5: lower 32-bits of fraction for mul by 2
+|		d6: temp for bit-field extracts
+|		d7: byte digit formation word;digit count {0,1}
+|		a0: pointer into memory for packed bcd string formation
+|
+
+|		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+|	THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF MOTOROLA 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.
+
+|BINSTR    idnt    2,1 | Motorola 040 Floating Point Software Package
+
+	|section	8
+
+	.include "fpsp.h"
+
+	.global	binstr
+binstr:
+	moveml	%d0-%d7,-(%a7)
+|
+| A1: Init d7
+|
+	moveql	#1,%d7			|init d7 for second digit
+	subql	#1,%d0			|for dbf d0 would have LEN+1 passes
+|
+| A2. Copy d2:d3 to d4:d5.  Start loop.
+|
+loop:
+	movel	%d2,%d4			|copy the fraction before muls
+	movel	%d3,%d5			|to d4:d5
+|
+| A3. Multiply d2:d3 by 8; extract msbs into d1.
+|
+	bfextu	%d2{#0:#3},%d1		|copy 3 msbs of d2 into d1
+	asll	#3,%d2			|shift d2 left by 3 places
+	bfextu	%d3{#0:#3},%d6		|copy 3 msbs of d3 into d6
+	asll	#3,%d3			|shift d3 left by 3 places
+	orl	%d6,%d2			|or in msbs from d3 into d2
+|
+| A4. Multiply d4:d5 by 2; add carry out to d1.
+|
+	asll	#1,%d5			|mul d5 by 2
+	roxll	#1,%d4			|mul d4 by 2
+	swap	%d6			|put 0 in d6 lower word
+	addxw	%d6,%d1			|add in extend from mul by 2
+|
+| A5. Add mul by 8 to mul by 2.  D1 contains the digit formed.
+|
+	addl	%d5,%d3			|add lower 32 bits
+	nop				|ERRATA ; FIX #13 (Rev. 1.2 6/6/90)
+	addxl	%d4,%d2			|add with extend upper 32 bits
+	nop				|ERRATA ; FIX #13 (Rev. 1.2 6/6/90)
+	addxw	%d6,%d1			|add in extend from add to d1
+	swap	%d6			|with d6 = 0; put 0 in upper word
+|
+| A6. Test d7 and branch.
+|
+	tstw	%d7			|if zero, store digit & to loop
+	beqs	first_d			|if non-zero, form byte & write
+sec_d:
+	swap	%d7			|bring first digit to word d7b
+	aslw	#4,%d7			|first digit in upper 4 bits d7b
+	addw	%d1,%d7			|add in ls digit to d7b
+	moveb	%d7,(%a0)+		|store d7b byte in memory
+	swap	%d7			|put LEN counter in word d7a
+	clrw	%d7			|set d7a to signal no digits done
+	dbf	%d0,loop		|do loop some more!
+	bras	end_bstr		|finished, so exit
+first_d:
+	swap	%d7			|put digit word in d7b
+	movew	%d1,%d7			|put new digit in d7b
+	swap	%d7			|put LEN counter in word d7a
+	addqw	#1,%d7			|set d7a to signal first digit done
+	dbf	%d0,loop		|do loop some more!
+	swap	%d7			|put last digit in string
+	lslw	#4,%d7			|move it to upper 4 bits
+	moveb	%d7,(%a0)+		|store it in memory string
+|
+| Clean up and return with result in fp0.
+|
+end_bstr:
+	moveml	(%a7)+,%d0-%d7
+	rts
+	|end