Oakland CPM Archive/oakcpm.iso/sigm/vol167/vb1.asm

Assembly Source File | 1984-04-29 | 14.9 KB | 1,030 lines

;    -------------------------------------------------------
;    Adaptation of VTI to use Solid State Music video board
;    model VB1-B with CP/M I-O routines on UAP's IMSAI 8080.
;        [Version October 27,1978]
;
;        VB1-B  -  Copyright (C) 1978
;        Universidad Autonoma de Puebla
;
;    written by Harold V. McIntosh, summer 1978, with
;    reference to: Harvey A. Cohen, "The Oznaki LIFE",
;    Dr. Dobbs Journal of Computer Calisthenics and
;    Orthodontia, volume 3, issue 4 (April 1978) pp. 10-11;
;    and with acknowledgements to the hospitality of the
;    Quantum Theory Project, University of Florida,
;    Gainesville, Florida.
;    ------------------------------------------------------

    org    0100H

    jmp main    ;create entry point for demonstration

;    -------------------------------------------------------
;    Constants defining screen size and location.  Note that
;    while the programmer has some discretion in assigning
;    these constants, there is highly implicit usage of the
;    assumption that the screen memory begins at a 1K Hex
;    boundary, and that the row length is a power of 2.
;    Thus the video board origin may be changed through its
;    address switches, and new parameters defined without
;    difficulty; nevertheless adaptation to an 80-column
;    board would require restructuring the subroutines.
;    -------------------------------------------------------

vorg:    equ    0F800H    ;origin of video screen memory area
vsiz:    equ    00400H    ;size of video screen memory area
rsiz    equ    00040H    ;length of a single display line
rmsk:    equ    rsiz-1    ;mask for single row addresses

;    -------------------------------------------------------
;    Data storage locations required by the subroutines.
;    -------------------------------------------------------

ma:    equ    00CC9H    ;bit mask to locate pixel within byte
wy:    equ    00CCAH    ;row count * 16  -  16 rows total
ex:    equ    00CCBH    ;column count * 4  -  64 columns total
ts:    equ    00CCCH    ;temporary storage

;    -----------------------------------------------------
;    Entry vector designed to systematize communication with
;    calling programs written in BASIC or other external
;    languages. These entry points will persist even though
;    the subroutines are revised, corrected, or otherwise
;    modified. A further advantage is that the same
;    arrangement can be used by the drivers for different
;    video boards, allowing program interchangability.
;    --------------------------------------------------------

vb1:    jmp    home    ;place cursor at screen center
    jmp    culi    ;illuminate the cursor
    jmp    cuex    ;extinguish the cursor
    jmp     cure    ;reverse the cursor
    jmp    cuse    ;sense the cursor (use jz afterward)
    jmp    xpl    ;move cursor right one pixel
    jmp    xmi    ;move cursor left one pixel
    jmp    ypl    ;move cursor up one pixel
    jmp    ymi    ;move cursor down one pixel
    jmp    blak    ;make the whole screen black
    jmp    whit    ;make the whole screen white
    jmp    reve    ;reverse the whole screen
    jmp    cart    ;form (ma, wy, ex) from (D,E)
    jmp    line    ;line segment with increments (dx,dy)
    jmp    ekspl    ;rotate whole screen right
    jmp    eksmi    ;rotate whole screen left
    jmp    wyepl    ;rotate whole screen up
    jmp    wyemi    ;rotate whole screen down
    jmp    ee    ;move cursor east one cell
    jmp    ww    ;move cursor west one cell
    jmp    nn    ;move cursor north one cell
    jmp    ss    ;move cursor south one cell
    jmp    kk    ;deactivate cell under cursor
    jmp    ll    ;activate cell under cursor
    jmp    hh    ;advance through one cycle of LIFE
    jmp    eas    ;rotate screen and cursor one cell east
    jmp    wes    ;rotate screen and cursor one cell west
    jmp    nor    ;rotate screen and cursor one cell north
    jmp    sou    ;rotate screen and cursor one cell south
    jmp    doli    ;illumate a two-pixel dot
    jmp    doex    ;extinguish a two-pixel dot
    jmp    xppl    ;move cursor one byte right
    jmp    xmmi    ;move cursor one byte left
    jmp    eksppl    ;rotate whole screen one byte right
    jmp    eksmmi    ;rotate whole screen one byte left

;    =======================================================

;    move cursor up one pixel

ypl:    lxi h,ma
    mov a,m
    ani 009H
    jnz yp1
    mov a,m
    rrc
    mov m,a
    ret
yp1:    rlc
    rlc
    mov m,a
    lda wy
    sui 010H
    sta wy
    ret

;    move cursor down one pixel

ymi:    lxi h,ma
    mov a,m
    ani 024H
    jnz ym1
    mov a,m
    rlc
    mov m,a
    ret
ym1:    rrc
    rrc
    mov m,a
    lda wy
    adi 010H
    sta wy
    ret

;    move cursor right one pixel

xpl:    lxi h,ma
    mov a,m
    ani 038H
    jnz xp1
    mov a,m
    rlc
    rlc
    rlc
    mov m,a
    ret
xp1:    rrc
    rrc
    rrc
    mov m,a
    lda ex
    adi 004H
    sta ex
    ret

;    move cursor left one pixel

xmi:    lxi h,ma
    mov a,m
    ani 007H
    jnz xm1
    mov a,m
    rrc
    rrc
    rrc
    mov m,a
    ret
xm1:    rlc
    rlc
    rlc
    mov m,a
    lda ex
    sui 004H
    sta ex
    ret

;    fast movement of cursor right two pixels

xppl:    lda ex
    adi 004H
    sta ex
    ret

;    fast movement of cursor left two pixels

xmmi:    lda ex
    sui 004H
    sta ex
    ret

;    load A with the bit mask, HL with a byte address
;    given the cursor positioning data at (ma,wy,ex)

dot:    lhld wy
    mov a,h
    mvi h,vorg/0400H
    dad h
    dad h
    rrc
    rrc
    ora l
    mov l,a
    lda ma
    ret

;    initialize cursor parameters

home:    lxi h,8080H
    shld wy
    mvi a,001H
    sta ma
    ret

;    extinguish the cursor

cuex:    call dot
    ora m
    mov m,a
    ret

;    light the cursor

culi:    call dot
    cma
    ana m
    mov m,a
    ret

;    reverse the cursor

cure:    call dot
    xra m
    mov m,a
    ret

;    sense the cursor

cuse:    call dot
    ana m
    ani 03FH
    ret

;    clear the whole screen to black

blak:    lxi d,vsiz
    lxi h,vorg
bl1:    mvi m,0FFH
    inx h
    dcr e
    jnz bl1
    dcr d
    jnz bl1
    ret

;    clear the whole screen to white

whit:    lxi d,vsiz
    lxi h,vorg
whi:    mvi m,080H
    inx h
    dcr e
    jnz whi
    dcr d
    jnz whi
    ret

;    reverse the whole screen

reve:    lxi d,vsiz
    lxi h,vorg
rev1:    mov a,m
    xri 03FH
    mov m,a
    inx h
    dcr e
    jnz rev1
    dcr d
    jnz rev1
    ret

;    transform cartesian coordinates in the form of x,y
;    transmitted through registers (D,E) to a mask and
;    byte address.

cart:    mvi b,018H
    mvi c,004H
    mov a,e
    cma
    adi 031H
car1:    cmp b
    jc car2
    sub b
car2:    cmc
    adc a
    dcr c
    jnz car1
    mov c,a
    ani 00FH
    rlc
    rlc
    rlc
    rlc
    sta wy
    mov a,c
    ani 0F0H
    jnz car3
    mvi a,008H
car3:    mov c,a
    mov a,d
    dcr a
    mov b,a
    rlc
    ani 0FCH
    sta ex
    mov a,b
    ani 001H
    mov a,c
    jnz car4
    rrc
    rrc
    rrc
car4:    sta ma
    ret

;    draw a line with increments dx,dy = (D,E).  Increment
;    may be + or - using complementary arithmetic, but ought
;    to be less than 64 in absolute value to avoid overflow
;    problems.

line:    lxi h,ypl
    mov a,e
    ora a
    jp lin1
    cma
    inr a
    mov e,a
    lxi h,ymi
lin1:    lxi b,xppl
    mov a,d
    ora a
    jp lin2
    cma
    inr a
    mov d,a
    lxi b,xmmi
lin2:    cmp e
    jnc lin3
    push h
    push b
    pop h
    pop b
    mov d,e
    mov e,a
lin3:    mov a,d
    sta ts
    mov a,e
    add a
    mov e,a
    sub d
    push psw
    sub d
    mov d,a
lin4:    pop psw
    push h
    lxi h,doli
    xthl
    cpi 001H
    jm lin5
    push h
    add d
    jmp lin6
lin5:    add e
lin6:    push b
    push psw
    lda ts
    dcr a
    sta ts
    jnz lin4
    pop psw
    ret

;    the movements in one byte necessary to shift the
;    whole screen right one pixel.

expl:    mov a,m
    ani 03FH
    mov b,a
    ani 007H
    rlc
    rlc
    rlc
    ora c
    mov c,a
    mov a,b
    rrc
    rrc
    rrc
    ani 007H
    mov b,c
    mov c,a
    ret

;    the movements within one byte necessary for shifting
;    the whole screen left one pixel.

exmi:    mov a,m
    ani 03FH
    mov b,a
    rrc
    rrc
    rrc
    ani 007H
    ora c
    mov c,a
    mov a,b
    ani 007H
    rlc
    rlc
    rlc
    mov b,c
    mov c,a
    ret

;    the movements necessary within one byte to shift the
;    whole screen down one pixel.

wymi:    mov a,m
    ani 03FH
    mov b,a
    ani 01BH
    rlc
    ora c
    mov c,a
    mov a,b
    rrc
    rrc
    ani 009H
    mov b,c
    mov c,a
    ret

;    the movements necessary within one byte to shift the
;    whole screen up one pixel.

wypl:    mov a,m
    ani 03FH
    mov b,a
    rrc
    ani 01BH
    ora c
    mov c,a
    mov a,b
    ani 009H
    rlc
    rlc
    mov b,c
    mov c,a
    ret

;    rotate the whole screen right one pixel

ekspl:    lxi h,vorg
    lxi d,rsiz-1
eksp1:    push h
    dad d
    call expl
    pop h
eksp2:    call expl
    mov a,b
    ori 080H
    mov m,a
    inx h
    mov a,l
    ani rmsk
    jnz eksp2
    mov a,h
    cpi (vorg+vsiz)/0100H
    jnz eksp1
    ret

;    rotate the whole screen left one pixel

eksmi:    lxi h,vorg+vsiz-1
    lxi d,-rsiz+1
eksm1:    push h
    dad d
    call exmi
    pop h
eksm2:    call exmi
    mov a,b
    ori 080H
    mov m,a
    mov a,l
    ani rmsk
    dcx h
    jnz eksm2
    mov a,h
    cpi (vorg/0100H)-1
    jnz eksm1
    ret

;    rotate the whole screen up one pixel.

wyepl:    lxi h,vorg+vsiz-1
wyep1:    lxi d,-vsiz+rsiz
    push h
    dad d
    call wypl
    pop h
    push h
    lxi d,-rsiz
wyep2:    call wypl
    mov a,b
    ori 080H
    mov m,a
    dad d
    mov a,h
    cpi (vorg/0100H)-1
    jnz wyep2
    pop h
    mov a,l
    ani rmsk
    dcx h
    jnz wyep1
    ret

;    rotate the whole screen down one pixel

wyemi:    lxi h,vorg
wyem1:    lxi d,vsiz-rsiz
    push h
    dad d
    call wymi
    pop h
    push h
    lxi d,rsiz
wyem2:    call wymi
    mov a,b
    ori 080H
    mov m,a
    dad d
    mov a,h
    cpi (vorg+vsiz)/0100H
    jnz wyem2
    pop h
    inx h
    mov a,l
    ani rmsk
    jnz wyem1
    ret

;    fast right rotation by two pixels = one byte

eksppl:    lxi h,vorg
    lxi d,rsiz-1
ekspp1:    push h
    dad d
    mov c,m
    pop h
ekspp2:    mov b,m
    mov m,c
    mov c,b
    inx h
    mov a,l
    ani rmsk
    jnz ekspp2
    mov a,h
    cpi (vorg+vsiz)/0100H
    jnz ekspp1
    ret

;    fast left rotate by two pixels = one byte

eksmmi:    lxi h,vorg+vsiz-1
    lxi d,-rsiz+1
eksmm1:    push h
    dad d
    mov c,m
    pop h
eksmm2:    mov b,m
    mov m,c
    mov c,b
    mov a,l
    ani rmsk
    dcx h
    jnz eksmm2
    mov a,h
    cpi (vorg/0100H)-1
    jnz eksmm1
    ret

;    Add to the neighbor count of adjoining cells according
;    to the bits in this byte.  We do the middle pixel,
;    adding to the count of three successive neighbors in
;    registers B,C,D.

alfa:    mov a,m
    rlc
    rlc
    rlc
    jc alf1
    inr b
    inr c
    inr d
alf1:    rlc
    jc alf2
    inr b
    inr d
alf2:    rlc
    rc
    inr b
    inr c
    inr d
    ret

;    shift the neighbor count as we move forward one byte in
;    a row scan

beta:    mov b,c
    mov c,d
    mvi d,00H
    inx h
    mov a,l
    ani 03FH
    rnz
    push d
    lxi d,-rsiz
    dad d
    pop d
    ret

;    PRINCIPAL PROGRAM for carrying out a cycle of LIFE.
;    Only the middle pixel in each byte is calculated
;    so that three passes are necessary after each of three
;    shifts. Two adjacent pixels are used, the right to hold
;    the present living status and the left for information
;    for the next cycle.

epsi:    lxi h,vorg+rsiz-1
gama:    mvi d,00H
    call alfa
    call beta
    call alfa
delt:    push h
    call beta
    call alfa
    xthl
    mov a,b
    cpi 002H
    jz eta
    cpi 003H
    jz zeta
    mov a,m
    ori 002H
    mov m,a
    jmp thet
zeta:    mov a,m
    ani 0FDH
    mov m,a
    jmp thet
eta:    mov a,m
    ani 0FDH
    mov e,a
    ani 010H
    rrc
    rrc
    rrc
    ora e
    mov m,a
thet:    pop h
    mov a,l
    ani rmsk
    jnz delt
    push d
    lxi d,2*rsiz-1
    dad d
    pop d
    mov a,h
    cpi (vorg+vsiz)/0100H
    jnz gama
    ret

;    updating loop, moving left pixel to right

cycl:    lxi h,vorg
cyc1:    mov a,m
    ani 007H
    mov b,a
    rlc
    rlc
    rlc
    ora b
    ori 080H
    mov m,a
    inx h
    mov a,h
    cpi (vorg+vsiz)/0100H
    jnz cyc1
    ret

;    execute a single cycle of LIFE by updating the middle
;    pixel and making three sweeps while shifting each time

hh:    call epsi
    call wyepl
    call epsi
    call wyepl
    call epsi
    call wyemi
    call wyemi
    jmp cycl

;    extinguish cursor, move two pixels east, light cursor

ee:    call cure
    call xppl
    jmp  cure

;    extinguish cursor, two pixels west, light cursor

ww:    call cure
    call xmmi
    jmp  cure

;    extinguish cursor, one pixel north, light cursor

nn:    call cure
    call ypl
    jmp  cure

;    extinguish cursor, one pixel south, light cursor

ss:    call cure
    call ymi
    jmp  cure

;    extinguish a life cell

kk:    call xpl
    call cuex
    jmp xmi

;    activate a life cell

ll:    call xpl
    call culi
    jmp  xmi

;    move whole screen right one life cell, with cursor

eas:    call eksppl
    jmp xppl

;    move the whole screen left one life cell, with cursor

wes:    call eksmmi
    jmp  xmmi

;    move the whole screen up one life cell, with cursor

nor:    call wyepl
    jmp  ypl

;    move the whole screen down one life cell, with cursor

sou:    call wyemi
    jmp  ymi

;    light a two-pixel dot

doli:    call culi
    call xpl
    call culi
    jmp xmi

;    extinguish a two-pixel dot

doex:    call cuex
    call xpl
    call cuex
    jmp xmi

;    =======================================================
;    driver subroutines for diverse demonstrations
;    =======================================================

bdos:    equ    0005H    ;entry point for CP/M service routines
morg:    equ    4000H    ;area for defining macros

;    build up one-byte decimal number from digit string
;    null string =1, minus creates negative modulo 256
;    to correct an error type four zeroes and start over
;    decm: places number in D, terminal character in A
;    coop: places number in D, terminal character in E

coop:    call decm
    mov e,a
    ret
decm:    mvi d,01H
    call read
    cpi '-'
    jnz dec1
    lxi h,dec3
    push h
    call read
dec1:    cpi '0'
    rc
    cpi '9'+1
    rnc
    mvi d,00H
dec2:    cpi '0'
    rc
    cpi '9'+1
    rnc
    sui '0'
    mov e,a
    mov a,d
    rlc
    rlc
    add d
    rlc
    add e
    mov d,a
    call read
    jmp dec2
dec3:    push sp
    mov a,d
    cma
    inr a
    mov d,a
    pop sp
    ret

;    get (D,E) = (X,Y); for example a pair of coordinates
;    first read d=x, then e=y

pair:    call decm
    push d
    call decm
    pop sp
    mov e,d
    mov d,a
    ret

;    place a dot with coordinates x,y on the screen

pp:    call pair
    call cart
    jmp culi

;    draw a line with increments (dx,dy)

ii:    call pair
    jmp line

;    repeat the subroutine in (H,L) for the number of times
;    in D.

rept:    mov a,e
    push h
    push d
    lxi b,repi
    push b
    pchl
repi:    pop d
    pop h
    dcr d
    rz
    jmp rept

;    turn one ASCII digit into a macro location
;    address is returned in (H,L)

mloc:    lxi h,0005H
    dad sp
    mov e,m
    mvi d,00H
    mvi m,01H
    lxi b,morg
    xchg
    dad h
    dad h
    dad h
    dad h
    dad h
    dad b
    ret

;    record a macro definition

mdef:    call mloc
mde1:    call coop
    mov m,d
    inx h
    mov m,e
    inx h
    mvi a,01BH
    cmp e
    rz
    push h
    lxi h,vect
    call rept
    pop h
    jmp mde1

;    execute a defined macro

mxec:    call mloc
    push h
mxe1:    pop h
    mov d,m
    inx h
    mov a,m
    inx h
    cpi 01BH
    rz
    cpi ')'
    jz rpar
    cpi '('
    jz lpar
    mov e,a
    push h
    lxi h,vect
    call rept
    jmp mxe1
rpar:    pop psw
    dcr a
    jz  rpa1
    pop h
    push h
    push psw
    push h
    jmp mxe1
rpa1:    xthl
    jmp mxe1
lpar:    push h
    mov a,d
    push psw
    push h
    jmp mxe1

;    directory vector for LIFE demonstration

vect:    cpi 'N'        ;rotate screen north
    jz  nor
    cpi 'S'        ;rotate screen south
    jz  sou
    cpi 'E'        ;rotate screen east
        jz  eas
    cpi 'W'        ;rotate screen west
    jz  wes
    cpi 06EH    ;'n' - move cursor north
    jz  nn
    cpi 073H    ;'s' - move cursor south
    jz  ss
    cpi 065H    ;'e' - move cursor east
    jz  ee
    cpi 077H    ;'w' - move cursor west
    jz  ww
    cpi 06BH    ;'k' - deactivate cell
    jz  kk
    cpi 06CH    ;'l' - activate cell under cursor
    jz  ll
    cpi 'C'        ;clear screen to black
    jz  blak
    cpi 'R'        ;reverse the screen
    jz  reve
    cpi 068H    ;'h' - advance one cycle of LIFE
    jz  hh
    cpi 067H    ;'g' - repeat cycles of LIFE
    jz  gg
    cpi '.'        ;reverse cursor illumination
    jz  cure
    cpi '!'
    jz mdef
    cpi '?'
    jz mxec
    cpi 069H
    jz  ii
    cpi 070H
    jz  pp
    cpi ';'        ;exit to monitor
    jz  0000H
vend:    ret

;    call hh repeatedly unless keyboard input is waiting

gg:    call stat
    rnz
    call hh
    jmp gg

;    read program using invariant CP/M calls

read:    push h
    push d
    push b
    mvi c,01H
    call bdos
    pop b
    pop d
    pop h
    ret

;    keyboard status using invariant CP/M calls

stat:    push h
    push d
    push b
    mvi c,0BH
    call bdos
    ora a
    pop b
    pop d
    pop h
    ret

;    MAIN PROGRAM for LIFE demonstration
;    commands consist of a count and a letter.  An operation
;    is repeated the number of times required, null and zero
;    both being taken as once.  The correspondence between
;    letters and operations is established by a sequence of
;    CPI's and JZ's in the array vect.

main:    call home
loop:    call coop
    lxi h,vect
    call rept
    jmp loop

    end