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From: ForthNet@willett.pgh.pa.us (ForthNet articles from GEnie)
Newsgroups: comp.lang.forth
Subject: Mathematical routines
Message-ID: <2451.UUL1.3#5129@willett.pgh.pa.us>
Date: 4 Mar 91 13:19:56 GMT
Organization: (n.) to be organized.  But that's not important right now.
Lines: 47


 Date: 02-26-91 (11:21)              Number: 1341 of 1349 (Echo)
   To: CROSBY STONE                  Refer#: NONE
 From: RAY DUNCAN                      Read: NO
 Subj: NUMBER? ETC.                  Status: PUBLIC MESSAGE
 Conf: FORTH (58)                 Read Type: GENERAL (+)

 Sorry about not getting back to you sooner.  I didn't find your file
 NUMBER.TXT until a couple of days ago.

 Nobody stuffs the vectors for NUMBER? /NUMBER and NUMBER, *except* for
 the various floating point overlays during their installation (the BIN
 file is read into memory, relocated, and then the "top" word in the
 overlay is executed which pokes the vectors so that the Forth
 interpreter/compiler will know how to interpret or compile floating
 point numbers).  If you load the SFP or I8087 overlay and *then* poke
 the vectors for NUMBER, /NUMBER and NUMBER? to point to your "own"
 versions of these words, the vectors will stay stable throughout the
 execution of your application.

 NUMBER? is the generalized ASCII-to-binary numeric conversion operation.
 It accepts the address of a counted string and returns a binary value
 and a flag (which indicates whether the string was a valid number or
 not, and if so which type of number) on the stack.  NUMBER? is always
 called by the Forth interpreter/compiler regardless of STATE.

 NUMBER, is called by the Forth interpreter/compiler *after* NUMBER? if
 STATE is nonzero (i.e. the system is "compiling").  NUMBER, looks at the
 flag left by NUMBER? and decides how to compile the binary value beneath
 the flag as a literal.

 /NUMBER is called by the Forth interpreter/compiler *after* NUMBER? if
 STATE is zero (i.e. the system is "interpreting").  /NUMBER looks at the
 flag left by NUMBER? and discards the flag and any other debris, leaving
 only a single, double, or floating point value on the stack.

 Accordingly, the three words NUMBER? NUMBER, /NUMBER are a matched set
 and must all be replaced together (by poking the vectors for these three
 words) or not at all.

 NET/Mail : LMI Forth Board, Los Angeles, CA (213) 306-3530
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