change a bit in a variable ?

[exxos]

In STOS there is a function "BCLR" which can clear a bit (or BSET set a bit) in a variable.. however, hisoft basic doesn't seem to have such a function :roll: I could convert the number to a string and use MID$ and convert back to a number, but that seems a bit shitty.. does anyone know of any better ways to manipulate bits in variables ?

[mikro]

In case that Hisoft Basic doesn't support logical operations (AND, XOR), that could be pretty tricky. :) If it does, then it's easy:

<input> XOR 01000000 <--- flips the 6th bit
<input> AND 01000000 <--- clears the 6th bit
<input> OR 01000000 <--- sets the 6th bit

[exxos]

Interesting..

I can't see how AND wousod clear a bit though.. As if bit zero was 0 on the input, ANDed with zero, the output would be zero. In fact it would clear all bits other than the bit which is set ?

NAND. Would make sense I think. As a high on bit 7 would result in a zero ?

[mikro]

Oops, you are right.

It should have been: <input> AND 10111111 <--- clears the 6th bit

Too hot! :)

[exxos]

Awesome thanks. I think logic operations are in hisoft, will check it out when I get home later.

Yeah not looking forward to the pending heatwave here over the next few days!

[tzok]

It's pretty common in C...

Set bit 3 (0 based index, so bit 3 is 4th bit):
a|=(1<<3)

Clear bit 3:
a&=~(1<<3)

<< - shift left
| - bitwise OR
& - bitwise AND
~ - bitwise NOT

Unfortunately Spectrum BASIC doesn't have bitwise operators, it only has logical ones :( I'm unsure if in HiSoft BASIC it is any different.

[exxos]

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