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- To: info-mcl
- Subject: Stack-consing double-floats...
- From: firstname.lastname@example.org (Bill Andersen)
- Date: 14 Jan 93 16:18:39 GMT
- Newsgroups: comp.lang.lisp.mcl
- Organization: U of Maryland, Dept. of Computer Science, Coll. Pk., MD 20742
- Sender: email@example.com
I want to allocate (and initialize from fixnums or short-floats)
some double-floats on the stack. I plan to pass the double floats
to a function which uses Erann Gat's FPC and coerce the result back
into a short-float for the return value.
I found an internal CCL macro: CCL::WITH-STACK-DOUBLE-FLOATS
which does what I want, but initializes the floats to 0.0. I
can't figure out how to initialize them to something else w/o
causing a new double-float to be consed. The macro expands
(ccl::with-stack-double-floats (x) <body-stuff>)
=> (let* (((x (locally (declare (notinline float)) (float 0 0.0)))))
(declare (dynamic-extent x))
There seems to be an extra nesting of parentheses around the
first argument to LET*, but functions using this macro seem to
compile ok. So I decided to try to write a macro which does
the same thing but allows me to initialize the value of the
stack-consed double. My macro expands to the exact same code
as CCL::WITH-STACK-DOUBLE-FLOATS, but with the first argument
to FLOAT replaced with an initialization form. When I try to
use this in a function, I get:
Error: While compiling ....
(x (locally (declare (notinline float))
(float <my-init-form> 0.0)))
is not a symbol.
The initialization form is a function call which returns a
short float and does not cons.
What gives? I'm stuck....
/ Bill Andersen (firstname.lastname@example.org) /
/ University of Maryland /
/ Department of Computer Science /
/ College Park, Maryland 20742 /