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Taqoz Reloaded v2.8 - Queues / Stacks using Mini-OOF — Parallax Forums

Taqoz Reloaded v2.8 - Queues / Stacks using Mini-OOF

bob_g4bbybob_g4bby Posts: 335
edited 2022-07-30 19:44 in Forth

I needed several queues to stream longs in and out of a test rig for dsp words. A queue would also seem to be a useful means of passing data between COGs. Here is a BUFFER class to enable that. Data can be read out in fifo (queue), lifo (stack) or array modes. There is a word TEST that demonstrates queue and stack modes of operation. Two methods BUFEMPTY? and BUFFULL? allow you to check buffer status. If data is written to an already full buffer:-

  • Used as a queue, only the latest data will be saved
  • Used as a stack, the bottom entry(s) will be lost

Don't forget to load Mini-OOF before loading this code:-

--- Buffer class ver 5 in Mini-OOF for Taqoz Reloaded v2.8 Bob Edwards July 2022
--- The buffer data type is long

IFDEF *BUFFERL*
    FORGET *BUFFERL*
}
pub *BUFFERL* ." Buffers of type long ver 5 using Mini-OOF" ;

4 := CELLS

--- BUFFER class definition

OBJECT CLASS
    4 VARI BUFADRL
    4 VARI BUFADRH
    4 VARI BUFHEAD
    4 VARI BUFTAIL
    1 VARI BUFSTATUS
    METHOD BUFINIT
    METHOD BUFEMPTY?
    METHOD BUFEMPTY
    METHOD BUFFULL?
    METHOD BUF!
    METHOD BUF@
    METHOD BUFPOP
    METHOD BUFADR@
    METHOD .BUF
END-CLASS BUFFER

private
--- buffer status
0 := partfull
1 := full
2 := empty
public

--- ensure buffer is circular, dir=1 is top address check, dir=0 bottom address check
pri PTRWRAP ( dir ptr -- ptr' )
    IF
        DUP THIS BUFADRH @ =
        IF
            DROP THIS BUFADRL @
        THEN
    ELSE
        DUP THIS BUFADRL @ <
        IF
            DROP THIS BUFADRH @ CELLS -
        THEN
    THEN
;

--- are HEAD and TAIL pointers equal?
pri PTR=    ( -- flag )
    THIS BUFHEAD @
    THIS BUFTAIL @ =
;

--- create a buffer, n longs in size, and set it as empty
pri noname                  ( n -- )
    WITH
        org@ >R
        DUP CELLS * org@ + org              --- allocate the buffer storage in data space
        R> DUP THIS BUFADRL !               --- save start address of buffer
        SWAP CELLS * + THIS BUFADRH !       --- save the top limit address of buffer
        THIS BUFEMPTY                       --- set HEAD and TAIL to ADDRL
    ENDWITH
; ANON BUFFER DEFINES BUFINIT

--- return true if the buffer is empty
pri noname                  ( -- flag )
    WITH
        THIS BUFSTATUS C@ empty =           --- return true if buffer empty
    ENDWITH
; ANON BUFFER DEFINES BUFEMPTY?

--- empty the buffer of all data
pri noname                  ( -- )
    WITH
        THIS BUFADRL @ DUP                  --- get the buffer start address
        THIS BUFHEAD !                      --- initialise the data input pointer
        THIS BUFTAIL !                      --- initialise the data output pointer
        empty THIS BUFSTATUS C!             --- set buffer status to empty
    ENDWITH
; ANON BUFFER DEFINES BUFEMPTY

--- return true if the buffer is full
pri noname                  ( -- flag )
    WITH
        THIS BUFSTATUS C@ full =            --- return true if buffer is full
    ENDWITH
; ANON BUFFER DEFINES BUFFULL?

--- write a long into the buffer
pri noname                  ( n -- )
    WITH
        THIS BUFFULL?
        IF THIS BUF@ DROP THEN              --- if the buffer is alreay full, make room
        THIS BUFHEAD @ CELLS +
        1 PTRWRAP
        DUP THIS BUFHEAD !                  --- increment the buffer head pointer
        !                                   --- and write the data n
        PTR=
        IF full ELSE partfull THEN
        THIS BUFSTATUS C!                   --- and update buffer status
    ENDWITH
; ANON BUFFER DEFINES BUF!

--- read a long from the front of the buffer (first in, first out)
pri noname                  ( -- n )
    WITH
        THIS BUFEMPTY?
        IF
            0                                   --- overreading, just return 0
        ELSE
            THIS BUFTAIL @ CELLS +
            1 PTRWRAP
            DUP THIS BUFTAIL !                  --- increment the buffer head pointer
            @                                   --- and read the data n
            PTR=
            IF empty ELSE partfull THEN
            THIS BUFSTATUS C!                   --- and update buffer status        
        THEN
    ENDWITH
; ANON BUFFER DEFINES BUF@

--- read a long from the back of the buffer like a stack ( first in, last out )
pri noname                  ( -- n )
    WITH
        THIS BUFEMPTY?
        IF
            0                                   --- overreading, just return 0
        ELSE
            THIS BUFHEAD @ DUP @ SWAP           --- read the data n ( n [BUFHEAD] -- )
            CELLS - 0 PTRWRAP THIS BUFHEAD !    --- decrement the HEAD pointer
            PTR=
            IF empty ELSE partfull THEN         --- update buffer status
            THIS BUFSTATUS C!                   --- and update buffer status
        THEN
    ENDWITH
    ; ANON BUFFER DEFINES BUFPOP

--- returns address of nth element, for use as a normal array
pri noname          ( -- adr )
    BUFADRL @ 
; ANON BUFFER DEFINES BUFADR@

pri noname 
    WITH
        CRLF ." BUFADRL   = " THIS BUFADRL @ .L
        CRLF ." BUFADRH   = " THIS BUFADRH @ .L
        CRLF ." BUFHEAD   = " THIS BUFHEAD @ .L
        CRLF ." BUFTAIL   = " THIS BUFTAIL @ .L
        CRLF ." BUFSTATUS = " THIS BUFSTATUS C@
        SWITCH
            partfull    CASE ." partfull" BREAK
            full        CASE ." full" BREAK
            empty       CASE ." empty" BREAK
    ENDWITH
; ANON BUFFER DEFINES .BUF

--- end of BUFFER class definition

--- Test of the buffer class
10 := bufsize
BUFFER NEW := MYBUF

pub TEST    ( -- )
CRLF CRLF
bufsize MYBUF BUFINIT                   CRLF ." Buffer initialised " bufsize . ." longs in size (do once only as space is allotted)"
MYBUF BUFEMPTY?                         CRLF ." BUFEMPTY? returns " .
MYBUF BUFFULL?                          CRLF ." BUFFULL? returns " .
bufsize 2+ FOR I MYBUF BUF! NEXT        CRLF ." Buffer overfilled on purpose"
MYBUF BUFEMPTY?                         CRLF ." BUFEMPTY? returns " .
MYBUF BUFFULL?                          CRLF ." BUFFULL? returns " .
                                        CRLF ." Now read all buffer, as a buffer"
bufsize FOR MYBUF BUF@ CRLF . NEXT      CRLF ." All buffer read as a buffer - note values 0,1 are lost" 
MYBUF BUFEMPTY?                         CRLF ." BUFEMPTY? returns " .
MYBUF BUFFULL?                          CRLF ." BUFFULL? returns " .
bufsize FOR I MYBUF BUF! NEXT           CRLF ." Buffer filled up again and now read again as a stack"
bufsize FOR MYBUF BUFPOP CRLF . NEXT    CRLF ." All buffer read as a stack"
MYBUF BUFEMPTY?                         CRLF ." BUFEMPTY? returns " .
MYBUF BUFFULL?                          CRLF ." BUFFULL? returns " .
;



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