I haven't written any C code for Chicken since version 3 days, and to save me some time re-learning., I'd like to see if anyone's willing to write some for me. What I need is an implementation of the four native IEEE procedures (single and double ref and set) in the R6RS bytevectors library, documented at <
http://www.r6rs.org/final/html/r6rs-lib/r6rs-lib-Z-H-3.html#node_sec_2.8>. I can't find any Scheme implementations that are both portable and portably accurate (I've experimented with SRFI 56 and the sample R6RS implementation at
r6rs.org).
The contract for the four routines is that they accept a byte vector and an offset, and read or write an inexact number into the bytevector as 4 or 8 bytes with the native endianism, depending on whether it is an ieee-single procedure or an ieee-double procedure. The easiest way to do this in C is with a couple of unions that map a float or double onto an array of 4 or 8 chars, like these:
union float_map {
float f;
char c[4];
}
union double_map {
double d;
char c[4];
}
This is in aid of SRFI 160, the proposed heterogeneous vector library for R7RS-large. Can anyone help? Thanks.