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+--- Thread: (16C) WSIZE? Determine word size (/thread-12710.html)
(16C) WSIZE? Determine word size - mfleming - 03-30-2019 09:27 PM
The 16C can set the word size from 1 to 64 bits but has no way to retrieve the value of that setting. So everyone ends up shifting a 1 leftward across a word until the carry is set. Here is a simple routine that only affects the X register, to which is returned the current word size.
Code:
(from DM16C)
001 LBL A | 43 22 A WSIZE?
002 CLX | 43 35 Don't disturb stack
003 STO I | 44 32 Counter initial value
004 CLX | 43 35 Don't disturb stack
005 1 | 1 Bit pattern to find word size
006 LBL 0 | 43 22 0
007 F? 4 | 43 6 4 Carry set?
008 GTO 1 | 22 1 Yes
009 SL | 42 A Shift bit across word into carry
010 ISZ | 43 24 Increment word size counter
011 GTO 0 | 22 0
012 GTO 0 | 22 0
013 LBL 1 | 43 22 1
014 CF 4 | 43 5 4 Don't leave carry set
015 CLX | 43 35 Don't disturb stack
016 RCL I | 45 32 Recall word size
017 RTN | 43 21RE: (16C) WSIZE? Determine word size - mfleming - 03-31-2019 01:45 AM
I'm embarrassed to say I've managed to make a right turn by taking three lefts! As cdmackay's program comment reminded me, there's a much simpler way to get the word size.
Code:
LBL A 43 22 A
CLx 43 35 Zero
f NOT 42 30 All ones
g B# 43 7 How many?
RTN 43 21NB: Replace "CLx" in the second line with "0" to preserve the content of the X register. This code is now a semi-permanent resident as LBL F in memory!
RE: (16C) WSIZE? Determine word size - cdmackay - 03-31-2019 02:36 PM
ah! yes, that's very nice
thanks for that.