paranoia.c

lcc,一个可变目标c语言编译器的源码

			Y = One;
			Y2 = Y;
			Z1 = Radix - One;
			FourD = Four * D;
			do  {
				if (Y2 > Z2) {
					Q = Radix;
					Y1 = Y;
					do  {
						X1 = FABS(Q + FLOOR(Half - Q / Y1) * Y1);
						Q = Y1;
						Y1 = X1;
						} while ( ! (X1 <= Zero));
					if (Q <= One) {
						Z2 = Y2;
						Z = Y;
						}
					}
				Y = Y + Two;
				X = X + Eight;
				Y2 = Y2 + X;
				if (Y2 >= FourD) Y2 = Y2 - FourD;
				} while ( ! (Y >= D));
			X8 = FourD - Z2;
			Q = (X8 + Z * Z) / FourD;
			X8 = X8 / Eight;
			if (Q != FLOOR(Q)) Anomaly = True;
			else {
				Break = False;
				do  {
					X = Z1 * Z;
					X = X - FLOOR(X / Radix) * Radix;
					if (X == One) 
						Break = True;
					else
						Z1 = Z1 - One;
					} while ( ! (Break || (Z1 <= Zero)));
				if ((Z1 <= Zero) && (! Break)) Anomaly = True;
				else {
					if (Z1 > RadixD2) Z1 = Z1 - Radix;
					do  {
						NewD();
						} while ( ! (U2 * D >= F9));
					if (D * Radix - D != W - D) Anomaly = True;
					else {
						Z2 = D;
						I = 0;
						Y = D + (One + Z) * Half;
						X = D + Z + Q;
						SR3750();
						Y = D + (One - Z) * Half + D;
						X = D - Z + D;
						X = X + Q + X;
						SR3750();
						NewD();
						if (D - Z2 != W - Z2) Anomaly = True;
						else {
							Y = (D - Z2) + (Z2 + (One - Z) * Half);
							X = (D - Z2) + (Z2 - Z + Q);
							SR3750();
							Y = (One + Z) * Half;
							X = Q;
							SR3750();
							if (I == 0) Anomaly = True;
							}
						}
					}
				}
			}
		if ((I == 0) || Anomaly) {
			BadCond(Failure, "Anomalous arithmetic with Integer < ");
			printf("Radix^Precision = %.7e\n", W);
			printf(" fails test whether sqrt rounds or chops.\n");
			SqRWrng = True;
			}
		}
	if (! Anomaly) {
		if (! ((MinSqEr < Zero) || (MaxSqEr > Zero))) {
			RSqrt = Rounded;
			printf("Square root appears to be correctly rounded.\n");
			}
		else  {
			if ((MaxSqEr + U2 > U2 - Half) || (MinSqEr > Half)
				|| (MinSqEr + Radix < Half)) SqRWrng = True;
			else {
				RSqrt = Chopped;
				printf("Square root appears to be chopped.\n");
				}
			}
		}
	if (SqRWrng) {
		printf("Square root is neither chopped nor correctly rounded.\n");
		printf("Observed errors run from %.7e ", MinSqEr - Half);
		printf("to %.7e ulps.\n", Half + MaxSqEr);
		TstCond (Serious, MaxSqEr - MinSqEr < Radix * Radix,
			"sqrt gets too many last digits wrong");
		}
	/*=============================================*/
	Milestone = 90;
	/*=============================================*/
	Pause();
	printf("Testing powers Z^i for small Integers Z and i.\n");
	N = 0;
	/* ... test powers of zero. */
	I = 0;
	Z = -Zero;
	M = 3.0;
	Break = False;
	do  {
		X = One;
		SR3980();
		if (I <= 10) {
			I = 1023;
			SR3980();
			}
		if (Z == MinusOne) Break = True;
		else {
			Z = MinusOne;
			PrintIfNPositive();
			N = 0;
			/* .. if(-1)^N is invalid, replace MinusOne by One. */
			I = - 4;
			}
		} while ( ! Break);
	PrintIfNPositive();
	N1 = N;
	N = 0;
	Z = A1;
	M = FLOOR(Two * LOG(W) / LOG(A1));
	Break = False;
	do  {
		X = Z;
		I = 1;
		SR3980();
		if (Z == AInvrse) Break = True;
		else Z = AInvrse;
		} while ( ! (Break));
	/*=============================================*/
		Milestone = 100;
	/*=============================================*/
	/*  Powers of Radix have been tested, */
	/*         next try a few primes     */
	M = NoTrials;
	Z = Three;
	do  {
		X = Z;
		I = 1;
		SR3980();
		do  {
			Z = Z + Two;
			} while ( Three * FLOOR(Z / Three) == Z );
		} while ( Z < Eight * Three );
	if (N > 0) {
		printf("Errors like this may invalidate financial calculations\n");
		printf("\tinvolving interest rates.\n");
		}
	PrintIfNPositive();
	N += N1;
	if (N == 0) printf("... no discrepancis found.\n");
	if (N > 0) Pause();
	else printf("\n");
	/*=============================================*/
	/*SPLIT
	}
#include "paranoia.h"
part6(){
*/
	Milestone = 110;
	/*=============================================*/
	printf("Seeking Underflow thresholds UfThold and E0.\n");
	D = U1;
	if (Precision != FLOOR(Precision)) {
		D = BInvrse;
		X = Precision;
		do  {
			D = D * BInvrse;
			X = X - One;
			} while ( X > Zero);
		}
	Y = One;
	Z = D;
	/* ... D is power of 1/Radix < 1. */
	do  {
		C = Y;
		Y = Z;
		Z = Y * Y;
		} while ((Y > Z) && (Z + Z > Z));
	Y = C;
	Z = Y * D;
	do  {
		C = Y;
		Y = Z;
		Z = Y * D;
		} while ((Y > Z) && (Z + Z > Z));
	if (Radix < Two) HInvrse = Two;
	else HInvrse = Radix;
	H = One / HInvrse;
	/* ... 1/HInvrse == H == Min(1/Radix, 1/2) */
	CInvrse = One / C;
	E0 = C;
	Z = E0 * H;
	/* ...1/Radix^(BIG Integer) << 1 << CInvrse == 1/C */
	do  {
		Y = E0;
		E0 = Z;
		Z = E0 * H;
		} while ((E0 > Z) && (Z + Z > Z));
	UfThold = E0;
	E1 = Zero;
	Q = Zero;
	E9 = U2;
	S = One + E9;
	D = C * S;
	if (D <= C) {
		E9 = Radix * U2;
		S = One + E9;
		D = C * S;
		if (D <= C) {
			BadCond(Failure, "multiplication gets too many last digits wrong.\n");
			Underflow = E0;
			Y1 = Zero;
			PseudoZero = Z;
			Pause();
			}
		}
	else {
		Underflow = D;
		PseudoZero = Underflow * H;
		UfThold = Zero;
		do  {
			Y1 = Underflow;
			Underflow = PseudoZero;
			if (E1 + E1 <= E1) {
				Y2 = Underflow * HInvrse;
				E1 = FABS(Y1 - Y2);
				Q = Y1;
				if ((UfThold == Zero) && (Y1 != Y2)) UfThold = Y1;
				}
			PseudoZero = PseudoZero * H;
			} while ((Underflow > PseudoZero)
				&& (PseudoZero + PseudoZero > PseudoZero));
		}
	/* Comment line 4530 .. 4560 */
	if (PseudoZero != Zero) {
		printf("\n");
		Z = PseudoZero;
	/* ... Test PseudoZero for "phoney- zero" violates */
	/* ... PseudoZero < Underflow or PseudoZero < PseudoZero + PseudoZero
		   ... */
		if (PseudoZero <= Zero) {
			BadCond(Failure, "Positive expressions can underflow to an\n");
			printf("allegedly negative value\n");
			printf("PseudoZero that prints out as: %g .\n", PseudoZero);
			X = - PseudoZero;
			if (X <= Zero) {
				printf("But -PseudoZero, which should be\n");
				printf("positive, isn't; it prints out as  %g .\n", X);
				}
			}
		else {
			BadCond(Flaw, "Underflow can stick at an allegedly positive\n");
			printf("value PseudoZero that prints out as %g .\n", PseudoZero);
			}
		TstPtUf();
		}
	/*=============================================*/
	Milestone = 120;
	/*=============================================*/
	if (CInvrse * Y > CInvrse * Y1) {
		S = H * S;
		E0 = Underflow;
		}
	if (! ((E1 == Zero) || (E1 == E0))) {
		BadCond(Defect, "");
		if (E1 < E0) {
			printf("Products underflow at a higher");
			printf(" threshold than differences.\n");
			if (PseudoZero == Zero) 
			E0 = E1;
			}
		else {
			printf("Difference underflows at a higher");
			printf(" threshold than products.\n");
			}
		}
	printf("Smallest strictly positive number found is E0 = %g .\n", E0);
	Z = E0;
	TstPtUf();
	Underflow = E0;
	if (N == 1) Underflow = Y;
	I = 4;
	if (E1 == Zero) I = 3;
	if (UfThold == Zero) I = I - 2;
	UfNGrad = True;
	switch (I)  {
		case	1:
		UfThold = Underflow;
		if ((CInvrse * Q) != ((CInvrse * Y) * S)) {
			UfThold = Y;
			BadCond(Failure, "Either accuracy deteriorates as numbers\n");
			printf("approach a threshold = %.17e\n", UfThold);;
			printf(" coming down from %.17e\n", C);
			printf(" or else multiplication gets too many last digits wrong.\n");
			}
		Pause();
		break;
	
		case	2:
		BadCond(Failure, "Underflow confuses Comparison, which alleges that\n");
		printf("Q == Y while denying that |Q - Y| == 0; these values\n");
		printf("print out as Q = %.17e, Y = %.17e .\n", Q, Y2);
		printf ("|Q - Y| = %.17e .\n" , FABS(Q - Y2));
		UfThold = Q;
		break;
	
		case	3:
		X = X;
		break;
	
		case	4:
		if ((Q == UfThold) && (E1 == E0)
			&& (FABS( UfThold - E1 / E9) <= E1)) {
			UfNGrad = False;
			printf("Underflow is gradual; it incurs Absolute Error =\n");
			printf("(roundoff in UfThold) < E0.\n");
			Y = E0 * CInvrse;
			Y = Y * (OneAndHalf + U2);
			X = CInvrse * (One + U2);
			Y = Y / X;
			IEEE = (Y == E0);
			}
		}
	if (UfNGrad) {
		printf("\n");
		sigsave = sigfpe;
		if (setjmp(ovfl_buf)) {
			printf("Underflow / UfThold failed!\n");
			R = H + H;
			}
		else R = SQRT(Underflow / UfThold);
		sigsave = 0;
		if (R <= H) {
			Z = R * UfThold;
			X = Z * (One + R * H * (One + H));
			}
		else {
			Z = UfThold;
			X = Z * (One + H * H * (One + H));
			}
		if (! ((X == Z) || (X - Z != Zero))) {
			BadCond(Flaw, "");
			printf("X = %.17e\n\tis not equal to Z = %.17e .\n", X, Z);
			Z9 = X - Z;
			printf("yet X - Z yields %.17e .\n", Z9);
			printf("    Should this NOT signal Underflow, ");
			printf("this is a SERIOUS DEFECT\nthat causes ");
			printf("confusion when innocent statements like\n");;
			printf("    if (X == Z)  ...  else");
			printf("  ... (f(X) - f(Z)) / (X - Z) ...\n");
			printf("encounter Division by Zero although actually\n");
			sigsave = sigfpe;
			if (setjmp(ovfl_buf)) printf("X / Z fails!\n");
			else printf("X / Z = 1 + %g .\n", (X / Z - Half) - Half);
			sigsave = 0;
			}
		}
	printf("The Underflow threshold is %.17e, %s\n", UfThold,
		   " below which");
	printf("calculation may suffer larger Relative error than ");
	printf("merely roundoff.\n");
	Y2 = U1 * U1;
	Y = Y2 * Y2;
	Y2 = Y * U1;
	if (Y2 <= UfThold) {
		if (Y > E0) {
			BadCond(Defect, "");
			I = 5;
			}
		else {
			BadCond(Serious, "");
			I = 4;
			}
		printf("Range is too narrow; U1^%d Underflows.\n", I);
		}
	/*=============================================*/
	/*SPLIT
	}
#include "paranoia.h"
part7(){
*/
	Milestone = 130;
	/*=============================================*/
	Y = - FLOOR(Half - TwoForty * LOG(UfThold) / LOG(HInvrse)) / TwoForty;
	Y2 = Y + Y;
	printf("Since underflow occurs below the threshold\n");
	printf("UfThold = (%.17e) ^ (%.17e)\nonly underflow ", HInvrse, Y);
	printf("should afflict the expression\n\t(%.17e) ^ (%.17e);\n", HInvrse, Y);
	V9 = POW(HInvrse, Y2);
	printf("actually calculating yields: %.17e .\n", V9);
	if (! ((V9 >= Zero) && (V9 <= (Radix + Radix + E9) * UfThold))) {
		BadCond(Serious, "this is not between 0 and underflow\n");
		printf("   threshold = %.17e .\n", UfThold);
		}
	else if (! (V9 > UfThold * (One + E9)))
		printf("This computed value is O.K.\n");
	else {
		BadCond(Defect, "this is not between 0 and underflow\n");
		printf("   threshold = %.17e .\n", UfThold);
		}
	/*=============================================*/
	Milestone = 140;
	/*=============================================*/
	printf("\n");
	/* ...calculate Exp2 == exp(2) == 7.389056099... */
	X = Zero;
	I = 2;
	Y = Two * Three;
	Q = Zero;
	N = 0;
	do  {
		Z = X;
		I = I + 1;
		Y = Y / (I + I);
		R = Y + Q;
		X = Z + R;
		Q = (Z - X) + R;
		} while(X > Z);
	Z = (OneAndHalf + One / Eight) + X / (OneAndHalf * ThirtyTwo);
	X = Z * Z;
	Exp2 = X * X;
	X = F9;
	Y = X - U1;
	printf("Testing X^((X + 1) / (X - 1)) vs. exp(2) = %.17e as X -> 1.\n",
		Exp2);
	for(I = 1;;) {
		Z = X - BInvrse;
		Z = (X + One) / (Z - (One - BInvrse));
		Q = POW(X, Z) - Exp2;
		if (FABS(Q) > TwoForty * U2) {
			N = 1;
	 		V9 = (X - BInvrse) - (One - BInvrse);
			BadCond(Defect, "Calculated");
			printf(" %.17e for\n", POW(X,Z));
			printf("\t(1 + (%.17e) ^ (%.17e);\n", V9, Z);
			printf("\tdiffers from correct value by %.17e .\n", Q);
			printf("\tThis much error may spoil financial\n");
			printf("\tcalculations involving tiny interest rates.\n");
			break;
			}
		else {
			Z = (Y - X) * Two + Y;
			X = Y;
			Y = Z;
			Z = One + (X - F9)*(X - F9);
			if (Z > One && I < NoTrials) I++;
			else  {
				if (X > One) {
					if (N == 0)
					   printf("Accuracy seems adequate.\n");
					break;
					}
				else {
					X = One + U2;
					Y = U2 + U2;
					Y += X;
					I = 1;
					}
				}
			}
		}
	/*=============================================*/
	Milestone = 150;
	/*=============================================*/
	printf("Testing powers Z^Q at four nearly extreme values.\n");
	N = 0;
	Z = A1;
	Q = FLOOR(Half - LOG(C) / LOG(A1));
	Break = False;
	do  {
		X = CInvrse;
		Y = POW(Z, Q);
		IsYeqX();
		Q = - Q;
		X = C;
		Y = POW(Z, Q);
		IsYeqX();
		if (Z < One) Break = True;
		else Z = AInvrse;
		} while ( ! (Break));
	PrintIfNPositive();
	if (N == 0) printf(" ... no discrepancies found.\n");
	printf("\n");
	
	/*=============================================*/
	Milestone = 160;
	/*=============================================*/
	Pause();
	printf("Searching for Overflow threshold:\n");
	printf("This may generate an error.\n");
	Y = - CInvrse;
	V9 = HInvrse * Y;
	sigsave = sigfpe;
	if (setjmp(ovfl_buf)) { I = 0; V9 = Y; goto overflow; }
	do {
		V = Y;
		Y = V9;
		V9 = HInvrse * Y;
		} while(V9 < Y);
	I = 1;
overflow:
	sigsave = 0;
	Z = V9;
	printf("Can `Z = -Y' overflow?\n");
	printf("Trying it on Y = %.17e .\n", Y);
	V9 = - Y;
	V0 = V9;
	if (V - Y == V + V0) printf("Seems O.K.\n");
	else {
		printf("finds a ");
		BadCond(Flaw, "-(-Y) differs from Y.\n");
		}
	if (Z != Y) {
		BadCond(Serious, "");
		printf("overflow past %.17e\n\tshrinks to %.17e .\n", Y, Z);
		}
	if (I) {
		Y = V * (HInvrse * U2 - HInvrse);
		Z = Y + ((One - HInvrse) * U2) * V;
		if (Z < V0) Y = Z;
		if (Y < V0) V = Y;
		if (V0 - V < V0) V = V0;
		}
	else {
		V = Y * (HInvrse * U2 - HInvrse);
		V = V + ((One - HInvrse) * U2) * Y;
		}
	printf("Overflow threshold is V  = %.17e .\n", V);
	if (I) printf("Overflow saturates at V0 = %.17e .\n", V0);
	else printf("There is no saturation value because the system traps on overflow.\n");
	V9 = V * One;
	printf("No Overflow should be signaled for V * 1 = %.17e\n", V9);
	V9 = V / One;
	printf("                           nor for V / 1 = %.17e .\n", V9);
	printf("Any overflow signal separating this * from the one\n");
	printf("above is a DEFECT.\n");
	/*=============================================*/
	Milestone = 170;
	/*=============================================*/
	if (!(-V < V && -V0 < V0 && -UfThold < V && UfThold < V)) {
		BadCond(Failure, "Comparisons involving ");
		printf("+-%g, +-%g\nand +-%g are confused by Overflow.",