89 lines
1.1 KiB
C++
89 lines
1.1 KiB
C++
/* Name: sum
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Syntax: sum(var, minval, maxval, expr)
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Input: cadr(p1) var
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caddr(p1) minval
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cadddr(p1) maxval
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caddddr(p1) expr
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Output: Sum on stack
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Notes: The original value of var is restored before the sum
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function returns.
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Expr is quoted. It is not evaluated until var is
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assigned minval.
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*/
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#include "stdafx.h"
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#include "defs.h"
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void
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eval_sum(void)
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{
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push(cadr(p1)); /* index expr is quoted */
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push(caddr(p1));
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eval();
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push(cadddr(p1));
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eval();
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push(caddddr(p1));
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sum();
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}
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#define F p1
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#define X p2
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void
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sum(void)
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{
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int h, i, j, k;
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F = pop();
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k = pop_integer();
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j = pop_integer();
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X = pop();
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if (j == (int) 0x80000000)
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stop("2nd arg in sum function: integer expected");
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if (k == (int) 0x80000000)
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stop("3rd arg in sum function: integer expected");
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h = tos;
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for (i = j; i <= k; i++) {
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push(F);
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push(X);
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push_integer(i);
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subst();
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eval();
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}
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add_all(tos - h);
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}
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#if SELFTEST
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static char *s[] = {
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"sum(n,0,10,(-1/3)^n)",
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"44287/59049",
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/* ensure index expr is quoted */
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"sum(i,1,3,i)",
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"6",
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};
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void
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test_sum(void)
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{
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test(__FILE__, s, sizeof s / sizeof (char *));
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}
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#endif
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