No need for Semaphore when data size is <= 32 bit ?

[itix]

@Karlos

Certain operations are atomic. For example if you wish to set flags
atomically you can have:

or.l #1, 4(a4)

This operation is never interrupted and there is nobody else who would modify data in between. Of course this works in assembler only because C compiler might not work this way.

[itix]

That is, normally in C you would use something like

Forbid()
globalflags |= 1;
Permit()

when in 68k assembler coder can use single or.l instruction without Forbid()/Permit() arbitration.

This is sometimes used when dealing with Intuition windows.

[itix]

@Jose & SamuraiCrow

It is possible implement atomically incrementing counter in PPC asm without using Forbid()/Permit() or Semaphore arbitration. But better use other more portable methods than asm.