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    Length: 5062 (0x13c6)
    Types: TextFile
    Notes: UNIX file
    Names: »bcmutil.c«

└─⟦f27320a65⟧ Bits:30001972 Commodore 900 hard disk image with partial source code
    └─⟦f4b8d8c84⟧ UNIX V7 Filesystem
        └─ ⟦this⟧ »cmd/bc/bcmutil.c« 

TextFile

#include <stdio.h>
#include <assert.h>
#include "bc.h"


/*
 *	Newscalar takes the rvalue pointed to by lval and initializes
 *	it to have a value of zero.
 */

newscalar(lval)
register rvalue	*lval;
{
	minit(&lval->mantissa);
	mcopy(mzero, &lval->mantissa);
	lval->scale = 0;
}


/*
 *	Newarray takes the array pointed to by alval and initializes it
 *	to have one element, which will have the value of zero.
 */

newarray(alval)
register array	*alval;
{
	alval->size = 1;
	alval->avalue = (rvalue *)mpalc(sizeof (rvalue));
	newscalar(alval->avalue);
}


/*
 *	Arfree frees all space associated with the array pointed to by
 *	`alv'.
 */

arfree(alv)
register array	*alv;
{
	register rvalue	*rp;
	register int	left;

	for (rp = alv->avalue, left = alv->size; --left >= 0; ++rp)
		mvfree(&rp->mantissa);
	mpfree(alv->avalue);
}


/*
 *	Pow10 returns a pointer to a mint which is 10 ^ `power'.
 *	Note that this pointer is to a static region, and hence
 *	should not be saved, but should be used immediately.
 *	Since pow10 is frequently used for scaleing, it first
 *	checks to see if the value being requested is the same
 *	as last time, and if so, simply returns it.
 */

mint	*
pow10(power)
register int	power;
{
	static int	oldpow = -1;
	static mint	oldres;

	if (power != oldpow) {
		if (power == 0)
			return (mone);
		spow(&ten, power, &oldres);
		oldpow = power;
	}
	return (&oldres);
}


/*
 *	Select returns the lvalue of the `indx'th item in the array
 *	`arry'.
 */

rvalue	*
select(arry, indx)
register array	*arry;
int		indx;
{
	register rvalue	*ptr;
	register int	nsize;

	if (indx < 0)
		bcmerr("Negative subscript");
	if (indx >= arry->size) {
		nsize = indx + ABUMP - indx % ABUMP;
	/*
	 *	Should be:
	 *	ptr = (rvalue *)realloc(arry->avalue,
	 *		nsize * (sizeof (rvalue)));
	 *	if (ptr == NULL)
	 *		die("Out of space");
	 *	But is:
	 */
		ptr = (rvalue *)mpalc(nsize * (sizeof (rvalue)));
		copy((char *)arry->avalue, (char *)ptr,
			arry->size * sizeof (rvalue));
		mpfree(arry->avalue);
	/*
	 *	End of kludge.
	 */
		arry->avalue = ptr;
		ptr += arry->size;
		do {
			newscalar(ptr++);
		} while (++arry->size < nsize);
	}
	return (&arry->avalue[indx]);
}


/*
 *	Shift sets the mint `b' to the mint `a' times 10 ^ `scnt'.
 *	If `scnt' is negative, then a divide (with truncation) is
 *	done.  If `scnt' is zero and `a' and `b' are the same, then
 *	no action is taken.
 */


shift(a, scnt, b)
register int	scnt;
mint	*a, *b;
{
	mint	temp;

	if (scnt > 0)
		mult(a, pow10(scnt), b);
	else if (scnt < 0) {
		minit(&temp);
		mdiv(a, pow10(-scnt), b, &temp);
		mvfree(&temp);
	} else if (a != b)
		mcopy(a, b);
}


/*
 *	Rescale adjusts the scale of the rvalue pointed to by `a'
 *	to `newsc'.
 */

rescale(a, newsc)
register rvalue	*a;
register int	newsc;
{
	shift(a, newsc - a->scale, a);
	a->scale = newsc;
}


/*
 *	Rtoint returns an int equal to the rvalue `a'.  Any
 *	fractional part is truncated.  If `a' is too large,
 *	then rtoint exits via bcerr.
 */

int
rtoint(a)
rvalue	*a;
{
	register int	res;
	mint	temp;

	minit(&temp);
	shift(&a->mantissa, - a->scale, &temp);
	if (mcmp(mminint, &temp) > 0 || mcmp(&temp, mmaxint) > 0)
		bcmerr("Too big for int");
	res = mtoi(&temp);
	mvfree(&temp);
	return (res);
}


/*
 *	Chkcall checks to make sure that a function is defined and has
 *	the right number of arguments.  `fnc' is a pointer to the
 *	dictionary entry for the function and `npars' is the number
 *	of parameters with which it is called.
 */

chkcall(fnc, npars)
register dicent	*fnc;
register int	npars;
{
	if (fnc->globalt != FUNCTION)
		bcmerr("`%s' not function", fnc->word);
	if (fnc->globalv.fvalue.body == NULL)
		bcmerr("Function `%s' not defined", fnc->word);
	if (fnc->globalv.fvalue.nparams != npars)
		bcmerr("Function `%s' needs %d arguments, got %d",
			fnc->word, fnc->globalv.fvalue.nparams, npars);
}


/*
 *	Pauto intializes the automatic variables needed by a bc function
 *	as part of the CALL instruction.  It also checks to make sure that
 *	there is room for them on the stack.  Pauto returns the value
 *	for tos after the CALL is completed (which is a pointer to the
 *	return state).  `fnc' is the function being called, tos is the
 *	old tos and limit is the last available stack entry.
 */

stkent	*
pauto(fnc, tos, limit)
register func	*fnc;
register stkent	*tos;
stkent		*limit;
{
	register type	*tp;
	int		left;

	left = fnc->nautos;
	if (tos + left >= limit)
		bcmerr("Out of runtime stack");
	++tos;
	for (tp = &fnc->types[fnc->nparams]; --left >= 0; ++tp, ++tos)
		switch (*tp) {
		case SCALAR:
			newscalar(&tos->rvalue);
			break;
		case ARRAY:
			tos->alvalue = (array *)mpalc(sizeof (array));
			newarray(tos->alvalue);
			break;
		default:
			assert(FALSE);
		}
	return (tos);
}


/*
 *	Newframe returns the new value for the frame pointer after
 *	calling the function `fcn'.  `tos' is the top of the stack
 *	after the CALL (note, this points to the saved state).
 */

stkent	*
newframe(fcn, tos)
register func	*fcn;
stkent		*tos;
{
	return (tos - (fcn->nparams + fcn->nautos));
}