[PicForth] Re: Another gotcha- @ and ! can break interrupts

[Samuel Tardieu]

>>>>> "Alex" == Alex Holden <alex at linuxhacker.org> writes:

Alex> These files define words called any-@ and any-! which are
Alex> sometimes called when you use '@' and '!'. any-@ and any-! use
Alex> suspend-interrupts and restore-interrupts to prevent interrupts
Alex> from occuring in the middle of a fetch or store.

Could you try the following picisr.fs version and tell me whether this
fixes your problem? It allows you to nest as many as 256
suspend-interrupts/restore-interrupts. The drawback are:

  - the code is a little longer (not much) than before for initial
    (non-nested) calls (and faster for nested calls)

  - it takes one more byte in memory

The generated code looks like:

        ; name: suspend-interrupts
        ; max return-stack depth: 0
0x000D  0AA5    incf    0x25,f
0x000E  0B25    decfsz  0x25,w
0x000F  0008    return  
0x0010  080B    movf    0x0B,w
0x0011  00A4    movwf   0x24
0x0012  138B    bcf     0x0B,7
0x0013  0008    return  
        ; name: restore-interrupts
        ; max return-stack depth: 0
0x0014  0B25    decfsz  0x25,f
0x0015  0008    return  
0x0016  1BA4    btfsc   0x24,7
0x0017  178B    bsf     0x0B,7
0x0018  0008    return  

  Sam
-- 
Samuel Tardieu -- sam at rfc1149.net -- http://www.rfc1149.net/sam

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