lsame.f

贝尔实验室多年开发的矩阵计算程序库的说明文件

      LOGICAL FUNCTION LSAME(CA,CB)
*
*  -- LAPACK auxiliary routine (version 3.1) --
*     Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..
*     November 2006
*
*     .. Scalar Arguments ..
      CHARACTER CA,CB
*     ..
*
*  Purpose
*  =======
*
*  LSAME returns .TRUE. if CA is the same letter as CB regardless of
*  case.
*
*  Arguments
*  =========
*
*  CA      (input) CHARACTER*1
*
*  CB      (input) CHARACTER*1
*          CA and CB specify the single characters to be compared.
*
* =====================================================================
*
*     .. Intrinsic Functions ..
      INTRINSIC ICHAR
*     ..
*     .. Local Scalars ..
      INTEGER INTA,INTB,ZCODE
*     ..
*
*     Test if the characters are equal
*
      LSAME = CA .EQ. CB
      IF (LSAME) RETURN
*
*     Now test for equivalence if both characters are alphabetic.
*
      ZCODE = ICHAR('Z')
*
*     Use 'Z' rather than 'A' so that ASCII can be detected on Prime
*     machines, on which ICHAR returns a value with bit 8 set.
*     ICHAR('A') on Prime machines returns 193 which is the same as
*     ICHAR('A') on an EBCDIC machine.
*
      INTA = ICHAR(CA)
      INTB = ICHAR(CB)
*
      IF (ZCODE.EQ.90 .OR. ZCODE.EQ.122) THEN
*
*        ASCII is assumed - ZCODE is the ASCII code of either lower or
*        upper case 'Z'.
*
          IF (INTA.GE.97 .AND. INTA.LE.122) INTA = INTA - 32
          IF (INTB.GE.97 .AND. INTB.LE.122) INTB = INTB - 32
*
      ELSE IF (ZCODE.EQ.233 .OR. ZCODE.EQ.169) THEN
*
*        EBCDIC is assumed - ZCODE is the EBCDIC code of either lower or
*        upper case 'Z'.
*
          IF (INTA.GE.129 .AND. INTA.LE.137 .OR.
     +        INTA.GE.145 .AND. INTA.LE.153 .OR.
     +        INTA.GE.162 .AND. INTA.LE.169) INTA = INTA + 64
          IF (INTB.GE.129 .AND. INTB.LE.137 .OR.
     +        INTB.GE.145 .AND. INTB.LE.153 .OR.
     +        INTB.GE.162 .AND. INTB.LE.169) INTB = INTB + 64
*
      ELSE IF (ZCODE.EQ.218 .OR. ZCODE.EQ.250) THEN
*
*        ASCII is assumed, on Prime machines - ZCODE is the ASCII code
*        plus 128 of either lower or upper case 'Z'.
*
          IF (INTA.GE.225 .AND. INTA.LE.250) INTA = INTA - 32
          IF (INTB.GE.225 .AND. INTB.LE.250) INTB = INTB - 32
      END IF
      LSAME = INTA .EQ. INTB
*
*     RETURN
*
*     End of LSAME
*
      END