B

Task/Bitwise-operations/Fortran/bitwise-operations-1.f

@@ -0,0 +1,27 @@
+integer :: i, j = -1, k = 42
+logical :: a
+
+i = bit_size(j)       ! returns the number of bits in the given INTEGER variable
+
+! bitwise boolean operations on integers
+i = iand(k, j)        ! returns bitwise AND of K and J
+i = ior(k, j)         ! returns bitwise OR of K and J
+i = ieor(k, j)        ! returns bitwise EXCLUSIVE OR of K and J
+i = not(j)            ! returns bitwise NOT of J
+
+! single-bit integer/logical operations (bit positions are zero-based)
+a = btest(i, 4)       ! returns logical .TRUE. if bit position 4 of I is 1, .FALSE. if 0
+i = ibclr(k, 8)       ! returns value of K with 8th bit position "cleared" (set to 0)
+i = ibset(k, 13)      ! returns value of K with 13th bit position "set" (set to 1)
+
+! multi-bit integer operations
+i = ishft(k, j)       ! returns value of K shifted by J bit positions, with ZERO fill
+                      !    (right shift if J < 0 and left shift if J > 0).
+i = ishftc(k, j)      ! returns value of K shifted CIRCULARLY by J bit positions
+                      !    (right circular shift if J < 0 and left if J > 0)
+i = ishftc(k, j, 20)  ! returns value as before except that ONLY the 20 lowest order
+                      !    (rightmost) bits are circularly shifted
+i = ibits(k, 7, 8)    ! extracts 8 contiguous bits from K starting at position 7 and
+                      !    returns them as the rightmost bits of an otherwise
+                      !    zero-filled integer. For non-negative K this is
+                      !    arithmetically equivalent to:   MOD((K / 2**7), 2**8)

Task/Bitwise-operations/Fortran/bitwise-operations-2.f

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+ call mvbits(k, 2, 4, j, 0)  ! copy a sequence of 4 bits from k starting at bit 2 into j starting at bit 0