*DECK R1MACH REAL FUNCTION R1MACH (I) C***BEGIN PROLOGUE R1MACH C***PURPOSE Return floating point machine dependent constants. C***LIBRARY SLATEC C***CATEGORY R1 C***TYPE SINGLE PRECISION (R1MACH-S, D1MACH-D) C***KEYWORDS MACHINE CONSTANTS C***AUTHOR Fox, P. A., (Bell Labs) C Hall, A. D., (Bell Labs) C Schryer, N. L., (Bell Labs) C***DESCRIPTION C C R1MACH can be used to obtain machine-dependent parameters for the C local machine environment. It is a function subprogram with one C (input) argument, and can be referenced as follows: C C A = R1MACH(I) C C where I=1,...,5. The (output) value of A above is determined by C the (input) value of I. The results for various values of I are C discussed below. C C R1MACH(1) = B**(EMIN-1), the smallest positive magnitude. C R1MACH(2) = B**EMAX*(1 - B**(-T)), the largest magnitude. C R1MACH(3) = B**(-T), the smallest relative spacing. C R1MACH(4) = B**(1-T), the largest relative spacing. C R1MACH(5) = LOG10(B) C C Assume single precision numbers are represented in the T-digit, C base-B form C C sign (B**E)*( (X(1)/B) + ... + (X(T)/B**T) ) C C where 0 .LE. X(I) .LT. B for I=1,...,T, 0 .LT. X(1), and C EMIN .LE. E .LE. EMAX. C C The values of B, T, EMIN and EMAX are provided in I1MACH as C follows: C I1MACH(10) = B, the base. C I1MACH(11) = T, the number of base-B digits. C I1MACH(12) = EMIN, the smallest exponent E. C I1MACH(13) = EMAX, the largest exponent E. C C To alter this function for a particular environment, the desired C set of DATA statements should be activated by removing the C from C column 1. Also, the values of R1MACH(1) - R1MACH(4) should be C checked for consistency with the local operating system. C C***REFERENCES P. A. Fox, A. D. Hall and N. L. Schryer, Framework for C a portable library, ACM Transactions on Mathematical C Software 4, 2 (June 1978), pp. 177-188. C***ROUTINES CALLED XERMSG C***REVISION HISTORY (YYMMDD) C 790101 DATE WRITTEN C 890213 REVISION DATE from Version 3.2 C 891214 Prologue converted to Version 4.0 format. (BAB) C 900315 CALLs to XERROR changed to CALLs to XERMSG. (THJ) C 900618 Added DEC RISC constants. (WRB) C 900723 Added IBM RS 6000 constants. (WRB) C 910710 Added HP 730 constants. (SMR) C 911114 Added Convex IEEE constants. (WRB) C 920121 Added SUN -r8 compiler option constants. (WRB) C 920229 Added Touchstone Delta i860 constants. (WRB) C 920501 Reformatted the REFERENCES section. (WRB) C 920625 Added CONVEX -p8 and -pd8 compiler option constants. C (BKS, WRB) C 930201 Added DEC Alpha and SGI constants. (RWC and WRB) C***END PROLOGUE R1MACH C INTEGER SMALL(2) INTEGER LARGE(2) INTEGER RIGHT(2) INTEGER DIVER(2) INTEGER LOG10(2) C REAL RMACH(5) SAVE RMACH C EQUIVALENCE (RMACH(1),SMALL(1)) EQUIVALENCE (RMACH(2),LARGE(1)) EQUIVALENCE (RMACH(3),RIGHT(1)) EQUIVALENCE (RMACH(4),DIVER(1)) EQUIVALENCE (RMACH(5),LOG10(1)) C C MACHINE CONSTANTS FOR THE AMIGA C ABSOFT FORTRAN COMPILER USING THE 68020/68881 COMPILER OPTION C C DATA SMALL(1) / Z'00800000' / C DATA LARGE(1) / Z'7F7FFFFF' / C DATA RIGHT(1) / Z'33800000' / C DATA DIVER(1) / Z'34000000' / C DATA LOG10(1) / Z'3E9A209B' / C C MACHINE CONSTANTS FOR THE AMIGA C ABSOFT FORTRAN COMPILER USING SOFTWARE FLOATING POINT C C DATA SMALL(1) / Z'00800000' / C DATA LARGE(1) / Z'7EFFFFFF' / C DATA RIGHT(1) / Z'33800000' / C DATA DIVER(1) / Z'34000000' / C DATA LOG10(1) / Z'3E9A209B' / C C MACHINE CONSTANTS FOR THE APOLLO C C DATA SMALL(1) / 16#00800000 / C DATA LARGE(1) / 16#7FFFFFFF / C DATA RIGHT(1) / 16#33800000 / C DATA DIVER(1) / 16#34000000 / C DATA LOG10(1) / 16#3E9A209B / C C MACHINE CONSTANTS FOR THE BURROUGHS 1700 SYSTEM C C DATA RMACH(1) / Z400800000 / C DATA RMACH(2) / Z5FFFFFFFF / C DATA RMACH(3) / Z4E9800000 / C DATA RMACH(4) / Z4EA800000 / C DATA RMACH(5) / Z500E730E8 / C C MACHINE CONSTANTS FOR THE BURROUGHS 5700/6700/7700 SYSTEMS C C DATA RMACH(1) / O1771000000000000 / C DATA RMACH(2) / O0777777777777777 / C DATA RMACH(3) / O1311000000000000 / C DATA RMACH(4) / O1301000000000000 / C DATA RMACH(5) / O1157163034761675 / C C MACHINE CONSTANTS FOR THE CDC 170/180 SERIES USING NOS/VE C C DATA RMACH(1) / Z"3001800000000000" / C DATA RMACH(2) / Z"4FFEFFFFFFFFFFFE" / C DATA RMACH(3) / Z"3FD2800000000000" / C DATA RMACH(4) / Z"3FD3800000000000" / C DATA RMACH(5) / Z"3FFF9A209A84FBCF" / C C MACHINE CONSTANTS FOR THE CDC 6000/7000 SERIES C C DATA RMACH(1) / 00564000000000000000B / C DATA RMACH(2) / 37767777777777777776B / C DATA RMACH(3) / 16414000000000000000B / C DATA RMACH(4) / 16424000000000000000B / C DATA RMACH(5) / 17164642023241175720B / C C MACHINE CONSTANTS FOR THE CELERITY C1260 C C DATA SMALL(1) / Z'00800000' / C DATA LARGE(1) / Z'7F7FFFFF' / C DATA RIGHT(1) / Z'33800000' / C DATA DIVER(1) / Z'34000000' / C DATA LOG10(1) / Z'3E9A209B' / C C MACHINE CONSTANTS FOR THE CONVEX C USING THE -fn COMPILER OPTION C C DATA RMACH(1) / Z'00800000' / C DATA RMACH(2) / Z'7FFFFFFF' / C DATA RMACH(3) / Z'34800000' / C DATA RMACH(4) / Z'35000000' / C DATA RMACH(5) / Z'3F9A209B' / C C MACHINE CONSTANTS FOR THE CONVEX C USING THE -fi COMPILER OPTION C C DATA RMACH(1) / Z'00800000' / C DATA RMACH(2) / Z'7F7FFFFF' / C DATA RMACH(3) / Z'33800000' / C DATA RMACH(4) / Z'34000000' / C DATA RMACH(5) / Z'3E9A209B' / C C MACHINE CONSTANTS FOR THE CONVEX C USING THE -p8 OR -pd8 COMPILER OPTION C C DATA RMACH(1) / Z'0010000000000000' / C DATA RMACH(2) / Z'7FFFFFFFFFFFFFFF' / C DATA RMACH(3) / Z'3CC0000000000000' / C DATA RMACH(4) / Z'3CD0000000000000' / C DATA RMACH(5) / Z'3FF34413509F79FF' / C C MACHINE CONSTANTS FOR THE CRAY C C DATA RMACH(1) / 200034000000000000000B / C DATA RMACH(2) / 577767777777777777776B / C DATA RMACH(3) / 377224000000000000000B / C DATA RMACH(4) / 377234000000000000000B / C DATA RMACH(5) / 377774642023241175720B / C C MACHINE CONSTANTS FOR THE DATA GENERAL ECLIPSE S/200 C NOTE - IT MAY BE APPROPRIATE TO INCLUDE THE FOLLOWING CARD - C STATIC RMACH(5) C C DATA SMALL / 20K, 0 / C DATA LARGE / 77777K, 177777K / C DATA RIGHT / 35420K, 0 / C DATA DIVER / 36020K, 0 / C DATA LOG10 / 40423K, 42023K / C C MACHINE CONSTANTS FOR THE DEC ALPHA C USING G_FLOAT C C DATA RMACH(1) / '00000080'X / C DATA RMACH(2) / 'FFFF7FFF'X / C DATA RMACH(3) / '00003480'X / C DATA RMACH(4) / '00003500'X / C DATA RMACH(5) / '209B3F9A'X / C C MACHINE CONSTANTS FOR THE DEC ALPHA C USING IEEE_FLOAT C C DATA RMACH(1) / '00800000'X / C DATA RMACH(2) / '7F7FFFFF'X / C DATA RMACH(3) / '33800000'X / C DATA RMACH(4) / '34000000'X / C DATA RMACH(5) / '3E9A209B'X / C C MACHINE CONSTANTS FOR THE DEC RISC C C DATA RMACH(1) / Z'00800000' / C DATA RMACH(2) / Z'7F7FFFFF' / C DATA RMACH(3) / Z'33800000' / C DATA RMACH(4) / Z'34000000' / C DATA RMACH(5) / Z'3E9A209B' / C C MACHINE CONSTANTS FOR THE DEC VAX C (EXPRESSED IN INTEGER AND HEXADECIMAL) C THE HEX FORMAT BELOW MAY NOT BE SUITABLE FOR UNIX SYSTEMS C THE INTEGER FORMAT SHOULD BE OK FOR UNIX SYSTEMS C C DATA SMALL(1) / 128 / C DATA LARGE(1) / -32769 / C DATA RIGHT(1) / 13440 / C DATA DIVER(1) / 13568 / C DATA LOG10(1) / 547045274 / C C DATA SMALL(1) / Z00000080 / C DATA LARGE(1) / ZFFFF7FFF / C DATA RIGHT(1) / Z00003480 / C DATA DIVER(1) / Z00003500 / C DATA LOG10(1) / Z209B3F9A / C C MACHINE CONSTANTS FOR THE ELXSI 6400 C (ASSUMING REAL*4 IS THE DEFAULT REAL) C C DATA SMALL(1) / '00800000'X / C DATA LARGE(1) / '7F7FFFFF'X / C DATA RIGHT(1) / '33800000'X / C DATA DIVER(1) / '34000000'X / C DATA LOG10(1) / '3E9A209B'X / C C MACHINE CONSTANTS FOR THE HARRIS 220 C C DATA SMALL(1), SMALL(2) / '20000000, '00000201 / C DATA LARGE(1), LARGE(2) / '37777777, '00000177 / C DATA RIGHT(1), RIGHT(2) / '20000000, '00000352 / C DATA DIVER(1), DIVER(2) / '20000000, '00000353 / C DATA LOG10(1), LOG10(2) / '23210115, '00000377 / C C MACHINE CONSTANTS FOR THE HONEYWELL 600/6000 SERIES C C DATA RMACH(1) / O402400000000 / C DATA RMACH(2) / O376777777777 / C DATA RMACH(3) / O714400000000 / C DATA RMACH(4) / O716400000000 / C DATA RMACH(5) / O776464202324 / C C MACHINE CONSTANTS FOR THE HP 730 C C DATA RMACH(1) / Z'00800000' / C DATA RMACH(2) / Z'7F7FFFFF' / C DATA RMACH(3) / Z'33800000' / C DATA RMACH(4) / Z'34000000' / C DATA RMACH(5) / Z'3E9A209B' / C C MACHINE CONSTANTS FOR THE HP 2100 C 3 WORD DOUBLE PRECISION WITH FTN4 C C DATA SMALL(1), SMALL(2) / 40000B, 1 / C DATA LARGE(1), LARGE(2) / 77777B, 177776B / C DATA RIGHT(1), RIGHT(2) / 40000B, 325B / C DATA DIVER(1), DIVER(2) / 40000B, 327B / C DATA LOG10(1), LOG10(2) / 46420B, 46777B / C C MACHINE CONSTANTS FOR THE HP 2100 C 4 WORD DOUBLE PRECISION WITH FTN4 C C DATA SMALL(1), SMALL(2) / 40000B, 1 / C DATA LARGE(1), LARGE(2) / 77777B, 177776B / C DATA RIGHT(1), RIGHT(2) / 40000B, 325B / C DATA DIVER(1), DIVER(2) / 40000B, 327B / C DATA LOG10(1), LOG10(2) / 46420B, 46777B / C C MACHINE CONSTANTS FOR THE HP 9000 C C DATA SMALL(1) / 00004000000B / C DATA LARGE(1) / 17677777777B / C DATA RIGHT(1) / 06340000000B / C DATA DIVER(1) / 06400000000B / C DATA LOG10(1) / 07646420233B / C C MACHINE CONSTANTS FOR THE IBM 360/370 SERIES, C THE XEROX SIGMA 5/7/9, THE SEL SYSTEMS 85/86 AND C THE PERKIN ELMER (INTERDATA) 7/32. C C DATA RMACH(1) / Z00100000 / C DATA RMACH(2) / Z7FFFFFFF / C DATA RMACH(3) / Z3B100000 / C DATA RMACH(4) / Z3C100000 / C DATA RMACH(5) / Z41134413 / C C MACHINE CONSTANTS FOR THE IBM PC C C DATA SMALL(1) / 1.18E-38 / C DATA LARGE(1) / 3.40E+38 / C DATA RIGHT(1) / 0.595E-07 / C DATA DIVER(1) / 1.19E-07 / C DATA LOG10(1) / 0.30102999566 / C C MACHINE CONSTANTS FOR THE IBM RS 6000 C C DATA RMACH(1) / Z'00800000' / C DATA RMACH(2) / Z'7F7FFFFF' / C DATA RMACH(3) / Z'33800000' / C DATA RMACH(4) / Z'34000000' / C DATA RMACH(5) / Z'3E9A209B' / C C MACHINE CONSTANTS FOR THE INTEL i860 C C DATA RMACH(1) / Z'00800000' / C DATA RMACH(2) / Z'7F7FFFFF' / C DATA RMACH(3) / Z'33800000' / C DATA RMACH(4) / Z'34000000' / C DATA RMACH(5) / Z'3E9A209B' / C C MACHINE CONSTANTS FOR THE PDP-10 (KA OR KI PROCESSOR) C C DATA RMACH(1) / "000400000000 / C DATA RMACH(2) / "377777777777 / C DATA RMACH(3) / "146400000000 / C DATA RMACH(4) / "147400000000 / C DATA RMACH(5) / "177464202324 / C C MACHINE CONSTANTS FOR PDP-11 FORTRAN SUPPORTING C 32-BIT INTEGERS (EXPRESSED IN INTEGER AND OCTAL). C C DATA SMALL(1) / 8388608 / C DATA LARGE(1) / 2147483647 / C DATA RIGHT(1) / 880803840 / C DATA DIVER(1) / 889192448 / C DATA LOG10(1) / 1067065499 / C C DATA RMACH(1) / O00040000000 / C DATA RMACH(2) / O17777777777 / C DATA RMACH(3) / O06440000000 / C DATA RMACH(4) / O06500000000 / C DATA RMACH(5) / O07746420233 / C C MACHINE CONSTANTS FOR PDP-11 FORTRAN SUPPORTING C 16-BIT INTEGERS (EXPRESSED IN INTEGER AND OCTAL). C C DATA SMALL(1), SMALL(2) / 128, 0 / C DATA LARGE(1), LARGE(2) / 32767, -1 / C DATA RIGHT(1), RIGHT(2) / 13440, 0 / C DATA DIVER(1), DIVER(2) / 13568, 0 / C DATA LOG10(1), LOG10(2) / 16282, 8347 / C C DATA SMALL(1), SMALL(2) / O000200, O000000 / C DATA LARGE(1), LARGE(2) / O077777, O177777 / C DATA RIGHT(1), RIGHT(2) / O032200, O000000 / C DATA DIVER(1), DIVER(2) / O032400, O000000 / C DATA LOG10(1), LOG10(2) / O037632, O020233 / C C MACHINE CONSTANTS FOR THE SILICON GRAPHICS C C DATA RMACH(1) / Z'00800000' / C DATA RMACH(2) / Z'7F7FFFFF' / C DATA RMACH(3) / Z'33800000' / C DATA RMACH(4) / Z'34000000' / C DATA RMACH(5) / Z'3E9A209B' / C C MACHINE CONSTANTS FOR THE SUN C C DATA RMACH(1) / Z'00800000' / C DATA RMACH(2) / Z'7F7FFFFF' / C DATA RMACH(3) / Z'33800000' / C DATA RMACH(4) / Z'34000000' / C DATA RMACH(5) / Z'3E9A209B' / C C MACHINE CONSTANTS FOR THE SUN C USING THE -r8 COMPILER OPTION C C DATA RMACH(1) / Z'0010000000000000' / C DATA RMACH(2) / Z'7FEFFFFFFFFFFFFF' / C DATA RMACH(3) / Z'3CA0000000000000' / C DATA RMACH(4) / Z'3CB0000000000000' / C DATA RMACH(5) / Z'3FD34413509F79FF' / C C MACHINE CONSTANTS FOR THE UNIVAC 1100 SERIES C C DATA RMACH(1) / O000400000000 / C DATA RMACH(2) / O377777777777 / C DATA RMACH(3) / O146400000000 / C DATA RMACH(4) / O147400000000 / C DATA RMACH(5) / O177464202324 / C C MACHINE CONSTANTS FOR THE Z80 MICROPROCESSOR C C DATA SMALL(1), SMALL(2) / 0, 256/ C DATA LARGE(1), LARGE(2) / -1, -129/ C DATA RIGHT(1), RIGHT(2) / 0, 26880/ C DATA DIVER(1), DIVER(2) / 0, 27136/ C DATA LOG10(1), LOG10(2) / 8347, 32538/ C C***FIRST EXECUTABLE STATEMENT R1MACH IF (I .LT. 1 .OR. I .GT. 5) CALL XERMSG ('SLATEC', 'R1MACH', + 'I OUT OF BOUNDS', 1, 2) C R1MACH = RMACH(I) RETURN C END