m68k/fpsp040/bindec.S

12 |		value in memory; d0 contains the k-factor sign-extended
13 |		to 32-bits.  The input may be either normalized,
18 |	Saves and Modifies: D2-D7,A2,FP2
22 |	A1.	Set RM and size ext;  Set SIGMA = sign of input.
23 |		The k-factor is saved for use in d7. Clear the
45 |		k-factor can dictate either the total number of digits,
67 |	A9.	Scale X -> Y.
74 |		compensated for by 'or-ing' in the INEX2 flag to
77 |	A11.	Restore original FPCR; set size ext.
87 |		or less than LEN -1 digits, adjust ILOG and repeat from
114 |		d2: upper 32-bits of mantissa for binstr
115 |		d3: scratch;lower 32-bits of mantissa for binstr
119 |		d7: k-factor
122 |		a2: pointer to FP_X; abs(original value) in ext
165 	moveml	%d2-%d7/%a2,-(%a7)
166 	fmovemx %fp0-%fp2,-(%a7)
168 | A1. Set RM and size ext. Set SIGMA = sign input;
169 |     The k-factor is saved for use in d7.  Clear BINDEC_FLG for
175 	fmovel	#rm_mode,%FPCR	|set RM and ext
177 	movel	%d0,%d7		|move k-factor to d7
217 |     ILOG is the log base 10 of the input value.  It is approx-
224 |	d0: k-factor/exponent
230 |	d7: k-factor/Unchanged
244 	movel	#-4933,%d6	|force ILOG = -4933
266 	fmovel	#0,%FPSR		|zero all of fpsr - nothing needed
277 |     LEN is the number of digits to be displayed.  The k-factor
293 |	d7: k-factor/Unchanged
306 	tstl	%d7		|branch on sign of k
307 	bles	k_neg		|if k <= 0, LEN = ILOG + 1 - k
308 	movel	%d7,%d4		|if k > 0, LEN = k
312 	subl	%d7,%d4		|subtract off k
339 |	----------------------------------------------
359 |	d0: exponent/scratch - final is 0
361 |	d3: x/scratch - offset ptr into PTENRM array
364 |	d6: ILOG/ILOG or k if ((k<=0)&(ILOG<k))
365 |	d7: k-factor/Unchanged
378 	tstl	%d7		|test sign of k
380 	cmpl	%d6,%d7		|test k - ILOG
381 	blts	k_pos		|if ILOG >= k, skip this
382 	movel	%d7,%d6		|if ((k<0) & (ILOG < k)) ILOG = k
384 	movel	%d6,%d0		|calc ILOG + 1 - LEN in d0
393 	cmpl	#0xffffecd4,%d0	|test iscale <= -4908
450 | A9. Scale X -> Y.
470 |	d7: k-factor/Unchanged
487 	fdivx	%fp1,%fp0		|calculate X / SCALE -> Y to fp0
493 	fmovemx %fp1-%fp1,-(%a7)	|load ETEMP with 10^ISCALE
494 	movel	8(%a0),-(%a7)	|load FPTEMP with input arg
495 	movel	4(%a0),-(%a7)
496 	movel	(%a0),-(%a7)
499 	clrl	-(%a7)		|clear lword on stack
502 	moveb	#BUSY_SIZE-4,1(%a7) |write current busy size
516 	fmulx	%fp1,%fp0		|calculate X * SCALE -> Y to fp0
521 |      for by 'or-ing' in the INEX2 flag to the lsb of Y.
531 |	d7: k-factor/Unchanged
549 | A11. Restore original FPCR; set size ext.
557 	andil	#0x00000030,USER_FPCR(%a6) |set size to ext,
566 |	d0: FPSR with AINEX cleared/FPCR with size set to ext
572 |	d7: k-factor/Unchanged
576 |	a6: temp pointer to FP_SCR2(a6) - orig value saved and restored
586 	moveml	%d0-%d1/%a0-%a1,-(%a7)	|save regs used by sintd0
587 	movel	L_SCR1(%a6),-(%a7)
588 	movel	L_SCR2(%a6),-(%a7)
593 	orl	#0x80000000,(%a0)		|if neg, use -Y
595 	movel	USER_FPSR(%a6),-(%a7)
601 	moveml	(%a7)+,%d0-%d1/%a0-%a1	|restore regs used by sint
608 |      or less than LEN -1 digits, adjust ILOG and repeat from
613 |      in extended precision, so the use of a previous power-of-ten
619 |	d0: FPCR with size set to ext/scratch final = 0
625 |	d7: k-factor/Unchanged
640 	bne	not_zr		|if non-zero, go to second test
642 | Compute 10^(LEN-1)
646 	subql	#1,%d0		|d0 = LEN -1
657 | 10^LEN-1 is computed for this test and A14.  If the input was
665 | Compare abs(YINT) to 10^(LEN-1) and 10^LEN
669 	fcmpx	%fp2,%fp0		|compare abs(YINT) with 10^(LEN-1)
727 |	d0: x/LEN call to binstr - final is 0
729 |	d2: x/ms 32-bits of mant of abs(YINT)
730 |	d3: x/ls 32-bits of mant of abs(YINT)
734 |	d7: k-factor/Unchanged
789 |	 32               16 15                0
790 |	-----------------------------------------
792 |	-----------------------------------------
795 | is non-zero, OPERR is signaled.  In all cases, all 4 digits are
800 |	d0: x/LEN call to binstr - final is 0
802 |	d2: x/ms 32-bits of exp fraction/scratch
803 |	d3: x/ls 32-bits of exp fraction
807 |	d7: k-factor/Unchanged
823 	fbeq	den_zero	|if zero, use k-factor or 4933
828 	tstl	%d7		|check sign of the k-factor
881 |	d0: x/scratch - final is x
887 |	d7: k-factor/Unchanged
915 	fmovemx (%a7)+,%fp0-%fp2
916 	moveml	(%a7)+,%d2-%d7/%a2