X-Git-Url: https://git.saurik.com/apple/security.git/blobdiff_plain/80e2389990082500d76eb566d4946be3e786c3ef..d8f41ccd20de16f8ebe2ccc84d47bf1cb2b26bbb:/Security/libsecurity_cryptkit/lib/giantPort_Generic.h

diff --git a/Security/libsecurity_cryptkit/lib/giantPort_Generic.h b/Security/libsecurity_cryptkit/lib/giantPort_Generic.h
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+/* Copyright (c) 1998,2011,2014 Apple Inc.  All Rights Reserved.
+ *
+ * NOTICE: USE OF THE MATERIALS ACCOMPANYING THIS NOTICE IS SUBJECT
+ * TO THE TERMS OF THE SIGNED "FAST ELLIPTIC ENCRYPTION (FEE) REFERENCE
+ * SOURCE CODE EVALUATION AGREEMENT" BETWEEN APPLE, INC. AND THE
+ * ORIGINAL LICENSEE THAT OBTAINED THESE MATERIALS FROM APPLE,
+ * INC.  ANY USE OF THESE MATERIALS NOT PERMITTED BY SUCH AGREEMENT WILL
+ * EXPOSE YOU TO LIABILITY.
+ ***************************************************************************
+ *
+ * giantPort_Generic.h - Generic giant definitions routines, used when
+ *			 no platform-specific version is available.
+ *
+ * Revision History
+ * ----------------
+ * 06 Apr 1998 at Apple
+ *	Created.
+ */
+
+#ifndef	_CK_NSGIANT_PORT_GENERIC_H_
+#define _CK_NSGIANT_PORT_GENERIC_H_
+
+#include "feeDebug.h"
+#include "platform.h"
+#include "giantIntegers.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*
+ * We'll be using the compiler's 64-bit long long for these routines.
+ *
+ * Mask for upper word.
+ */
+#define GIANT_UPPER_DIGIT_MASK	(~(unsigned long long(GIANT_DIGIT_MASK)))
+
+/*
+ * Multiple-precision arithmetic routines/macros.
+ */
+
+/*
+ * Add two digits, return sum. Carry bit returned as an out parameter.
+ * This should work any size giantDigits up to unsigned int.
+ */
+static inline giantDigit giantAddDigits(
+	giantDigit dig1,
+	giantDigit dig2,
+	giantDigit *carry)			/* RETURNED, 0 or 1 */
+{
+	giantDigit sum = dig1 + dig2;
+
+	if((sum < dig1) || (sum < dig2)) {
+	 	*carry = 1;
+	}
+	else {
+		*carry = 0;
+	}
+	return sum & GIANT_DIGIT_MASK;
+}
+
+/*
+ * Add a single digit value to a double digit accumulator in place.
+ * Carry out of the MSD of the accumulator is not handled.
+ * This should work any size giantDigits up to unsigned int.
+ */
+static inline void giantAddDouble(
+	giantDigit *accLow,			/* IN/OUT */
+	giantDigit *accHigh,			/* IN/OUT */
+	giantDigit val)
+{
+	giantDigit sumLo = *accLow + val;
+
+	if((sumLo < *accLow) || (sumLo < val)) {
+	    (*accHigh)++;
+	    #if	FEE_DEBUG
+	    if(*accHigh == 0) {
+	        CKRaise("giantAddDouble overflow");
+	    }
+	    #endif	/* FEE_DEBUG */
+	}
+	*accLow = sumLo;
+}
+
+/*
+ * Subtract a - b, return difference. Borrow bit returned as an out parameter.
+ * This should work any size giantDigits up to unsigned int.
+ */
+static inline giantDigit giantSubDigits(
+	giantDigit a,
+	giantDigit b,
+	giantDigit *borrow)			/* RETURNED, 0 or 1 */
+{
+	giantDigit diff = a - b;
+
+	if(a < b) {
+		*borrow = 1;
+	}
+	else {
+		*borrow = 0;
+	}
+	return diff;
+}
+
+/*
+ * Multiply two digits, return two digits.
+ * This should work for 16 or 32 bit giantDigits, though it's kind of
+ * inefficient for 16 bits.
+ */
+static inline void giantMulDigits(
+	giantDigit	dig1,
+	giantDigit	dig2,
+ 	giantDigit	*lowProduct,		/* RETURNED, low digit */
+	giantDigit	*hiProduct)		/* RETURNED, high digit */
+{
+	unsigned long long dprod;
+
+	dprod = (unsigned long long)dig1 * (unsigned long long)dig2;
+	*hiProduct = (giantDigit)(dprod >> GIANT_BITS_PER_DIGIT);
+	*lowProduct = (giantDigit)dprod;
+}
+
+/*
+ * Multiply a vector of giantDigits, candVector, by a single giantDigit,
+ * plierDigit, adding results into prodVector. Returns m.s. digit from
+ * final multiply; only candLength digits of *prodVector will be written.
+ */
+static inline giantDigit VectorMultiply(
+	giantDigit plierDigit,
+	giantDigit *candVector,
+	unsigned candLength,
+	giantDigit *prodVector)
+{
+	unsigned candDex;		// index into multiplicandVector
+    	giantDigit lastCarry = 0;
+	giantDigit prodLo;
+	giantDigit prodHi;
+
+	for(candDex=0; candDex<candLength; ++candDex) {
+	    /*
+	     * prod = *(candVector++) * plierDigit + *prodVector + lastCarry
+	     */
+	    giantMulDigits(*(candVector++),
+		plierDigit,
+		&prodLo,
+		&prodHi);
+	    giantAddDouble(&prodLo, &prodHi, *prodVector);
+	    giantAddDouble(&prodLo, &prodHi, lastCarry);
+
+	    /*
+	     * *(destptr++) = prodHi;
+	     * lastCarry = prodLo;
+	     */
+	    *(prodVector++) = prodLo;
+	    lastCarry = prodHi;
+	}
+
+	return lastCarry;
+}
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#endif	/*_CK_NSGIANT_PORT_GENERIC_H_*/