MAP
BNOT(LONG pBitmap, LONG pMask),LONG
END
BNOT PROCEDURE (LONG pBitmap, LONG pMask)
CODE
RETURN BXOR(pBitMap,(BAND(pBitMap,pMask)))
Thank you very much Jeff!!
Jeff’s way works but the more traditional way is a “NOT AND” or “AND Complement”
Val2 = BAND( Value1, BXOR( BitsOffMask , 0FFFFFFFFh) )
or
Val2 = BAND( Value1, BXOR( BitsOffMask , -1 ) ) !LONG -1 = 0FFFFFFFFh
I find this “And Complement” easy to remember.
The BXOR( Mask , 0FFFFFFFFh ) is the “1’s Complement” which “Flips” all the Bits.
So the 1 bit in the Off Mask is now 0, and all the 0’s are 1.
Then BAND( Value1, Complement Mask ) leaves as 1 all Bits that were =1, but that 0.
Example to Turn Off the Font Style Italic bit
FONT:Regular EQUATE (400) ! 10010000b 0190h
FONT:Weight EQUATE (07FFH)
FONT:Italic EQUATE (01000H) ! 00010000 00000000b
Use this BAND( Style, BXOR( Font:Italic, -1))
First Complement the Bits to Turn Off which set All Bits as 1 but that single 10000h bit
BXOR( FONT:Italic , 0FFFFFFFFh)
-----------------> = FFFFEFFFh = 11111111 11111111 11101111 11111111b
Then AND(, Mask Complement) returns all but the Italic bit: BAND( Style, 0FFFFEFFFh )
Then BAND( Style, 0FFFFEFFFh ) i.e. AND(, Mask Complement) returns all but the Italic bit.
In a Signed LONG Integer a -1 is 0FFFFFFFFh so this can be used for less code as BXOR(,-1) to complement. Clarion does not have a Bitwise NOT operator.
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Added on GitHub an old tool Bit Mapper that takes a LONG and shows it split into all the Bits, Nibbles and Bytes.
I made it for working with Windows API functions like GetWindowLong() where the Styles have a lot of bit flags. It can take hex constants in C/C++/C# style 0x123ABC as you would find in the SDK .H files. Also VB style &H123ABC since there are many API examples in VB6.
You can test Clarion Bitwise functions BAND BOR BXOR BSHIFT to see the results.
The “~AND” button is an AND Complement to turn off bits. The Plus / Minus can show how they are not Bit Operations and can mess up your map.
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That looks Neat-O and useful.
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Very nice Carl!! I look forward to checking it out!