53 lines
1.1 KiB
C
53 lines
1.1 KiB
C
/*
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(c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
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See the copyright notice in the ACK home directory, in the file "Copyright".
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*/
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/* $Header$ */
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/*
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CONVERT FLOAT TO SIGNED (CFI m n)
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N.B. The caller must know what it is getting.
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A LONG is always returned. If it is an
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integer the high byte is cleared first.
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*/
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#include "FP_trap.h"
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#include "FP_types.h"
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#include "FP_shift.h"
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long
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cfi(ds,ss,src)
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int ds; /* destination size (2 or 4) */
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int ss; /* source size (4 or 8) */
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DOUBLE src; /* assume worst case */
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{
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EXTEND buf;
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long new;
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short max_exp;
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extend(&src.d[0],&buf,ss); /* get extended format */
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if (buf.exp < 0) { /* no conversion needed */
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src.d[ss == 8] = 0L;
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return(0L);
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}
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max_exp = (ds << 3) - 2; /* signed numbers */
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/* have more limited max_exp */
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if (buf.exp > max_exp) {
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if (buf.exp == max_exp+1 && buf.sign && buf.m1 == NORMBIT &&
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buf.m2 == 0L) {
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}
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else {
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trap(EIOVFL); /* integer overflow */
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buf.exp %= max_exp; /* truncate */
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}
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}
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new = buf.m1 >> (31-buf.exp);
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if (buf.sign)
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new = -new;
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done:
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src.d[ss == 8] = new;
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return(new);
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}
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