From 11da511c784eca003deb90c23570f0873954e0de Mon Sep 17 00:00:00 2001
From: Duncan Wilkie <antigravityd@gmail.com>
Date: Sat, 18 Nov 2023 06:11:09 -0600
Subject: Initial commit.

---
 ic-reals-6.3/math-lib/sqrt_Q.c~ | 140 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 140 insertions(+)
 create mode 100644 ic-reals-6.3/math-lib/sqrt_Q.c~

(limited to 'ic-reals-6.3/math-lib/sqrt_Q.c~')

diff --git a/ic-reals-6.3/math-lib/sqrt_Q.c~ b/ic-reals-6.3/math-lib/sqrt_Q.c~
new file mode 100644
index 0000000..0a59773
--- /dev/null
+++ b/ic-reals-6.3/math-lib/sqrt_Q.c~
@@ -0,0 +1,140 @@
+/*
+ * Copyright (C) 2000, Imperial College
+ *
+ * This file is part of the Imperial College Exact Real Arithmetic Library.
+ * See the copyright notice included in the distribution for conditions
+ * of use.
+ */
+
+#include <stdio.h>
+#include "real.h"
+#include "real-impl.h"
+
+/*
+ * It would be better to use a union of three int's and three mpz_t's and
+ * then go to the bignumns when we overflow a machine word.
+ */
+typedef struct {
+	mpz_t a, b, c;
+} RatSqrtData;
+
+static int doneInit = 0;
+
+static void ratSqrtCont();
+static bool emitDigitFromRatSqrt(RatSqrtData *, Digit *);
+
+Real
+sqrt_QInt(int a, int b)
+{
+	RatSqrtData *rsd;
+	Cls *cls;
+	DigsX *digsX;
+
+	if (!doneInit) {
+		registerForceFunc(ratSqrtCont, "ratSqrtCont", 3);
+		doneInit++;
+	}
+
+	if ((rsd = (RatSqrtData *) malloc(sizeof(RatSqrtData))) == NULL)
+		Error(FATAL, E_INT, "sqrt_QInt", "malloc failed");
+
+	mpz_init_set_ui(rsd->a, a);
+	mpz_init_set_ui(rsd->b, b);
+	mpz_init_set_ui(rsd->c, a - b);
+
+	cls = allocCls(ratSqrtCont, (void *) rsd);
+	cls->tag.isSigned = FALSE;
+
+	digsX = allocDigsX();
+	digsX->x = (Real) cls;
+	digsX->force = ratSqrtCont;
+
+	if (DAVINCI) {
+		beginGraphUpdate();
+		newEdgeToOnlyChild(digsX, cls);
+		endGraphUpdate();
+	}
+
+	return (Real) digsX;
+}
+
+Real
+sqrt_QZ(mpz_t a, mpz_t b)
+{
+	RatSqrtData *rsd;
+	Cls *cls;
+	DigsX *digsX;
+
+	if (!doneInit) {
+		registerForceFunc(ratSqrtCont, "ratSqrtCont", 3);
+		doneInit++;
+	}
+
+	if ((rsd = (RatSqrtData *) malloc(sizeof(RatSqrtData))) == NULL)
+		Error(FATAL, E_INT, "sqrt_QZ", "malloc failed");
+
+	mpz_init_set(rsd->a, a);
+	mpz_init_set(rsd->b, b);
+	mpz_init(rsd->c);
+	mpz_sub(rsd->c, rsd->a, rsd->b);
+
+	cls = allocCls(ratSqrtCont, (void *) rsd);
+	cls->tag.isSigned = FALSE;
+
+	digsX = allocDigsX();
+	digsX->x = (Real) cls;
+	digsX->force = ratSqrtCont;
+
+	if (DAVINCI) {
+		beginGraphUpdate();
+		newEdgeToOnlyChild(digsX, cls);
+		endGraphUpdate();
+	}
+
+	return (Real) digsX;
+}
+
+static void
+ratSqrtCont()
+{
+	DigsX *digsX;
+	Cls *cls;
+	int digitsNeeded;
+	RatSqrtData *rsd;
+
+	digsX = (DigsX *) POP;
+	digitsNeeded = (int) POP;
+	cls = (Cls *) digsX->x;
+
+	rsd = (RatSqrtData *) cls->userData;
+
+	emitDigits(digsX, (edf) emitDigitFromRatSqrt, (void *) rsd, digitsNeeded);
+	newDigsX(digsX);
+}
+
+static bool
+emitDigitFromRatSqrt(RatSqrtData *rsd, Digit *d)
+{
+	mpz_sub(tmpd_z, rsd->b, rsd->a);
+	mpz_mul_2exp(tmpd_z, tmpd_z, 1);
+	mpz_add(tmpd_z, tmpd_z, rsd->c);
+
+	switch (mpz_sgn(tmpd_z)) {
+		case 0 :
+		case 1 :
+			*d = DNEG;
+			mpz_mul_2exp(rsd->a, rsd->a, 2);  /* a = 4a */
+			mpz_set(rsd->b, tmpd_z);
+			break;
+		case -1 :
+			*d = DPOS;
+			mpz_neg(rsd->a, tmpd_z);
+			mpz_mul_2exp(rsd->b, rsd->b, 2);  /* b = 4b */
+			break;
+		default :
+			Error(FATAL, E_INT, "emitDigitFromRatSqrt",
+							"bad value returned by mpz_sgn");
+			break;
+	}
+	return TRUE;
+}
-- 
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