ProfitPress Mega CDROM2 …eeware (MSDOS)(1992)(Eng)/ProfitPress-MegaCDROM2.B6I/GRAPHICS/MISC/FRPOR172.ZIP/LSYSA.ASM

Assembly Source File | 1992-01-29 | 3.8 KB | 218 lines

; LSYSA.ASM: assembler support routines for optimized L-System code
; Nicholas Wilt, 11/13/91.
;

.MODEL    MEDIUM,C

EXTRN    reverse:BYTE,angle:BYTE,maxangle:BYTE,dmaxangle:BYTE
EXTRN    xpos:DWORD,ypos:DWORD,ssize:DWORD
EXTRN    realangle:DWORD
EXTRN    lsys_Xmin:DWORD,lsys_Xmax:DWORD,lsys_Ymin:DWORD,lsys_Ymax:DWORD
EXTRN    sins:DWORD
EXTRN    coss:DWORD
EXTRN    overflow:WORD

.CODE

decangle    PROC    NEAR
    mov    al,angle
    or    al,al
    jz    DecAngle0
    dec    angle
    ret
DecAngle0:
    mov    al,dmaxangle
    mov    angle,al
    ret
decangle    ENDP

incangle    PROC    NEAR
    mov    al,angle
    inc    al
    cmp    al,maxangle
    jnz    IncWriteAngle
    xor    ax,ax
IncWriteAngle:
    mov    angle,al
    ret
incangle    ENDP

    PUBLIC    lsys_doplus

lsys_doplus    PROC
    cmp    reverse,0
    jnz    PlusIncAngle
    call    decangle
    ret
PlusIncAngle:
    call    incangle
    ret
lsys_doplus    ENDP

    PUBLIC    lsys_dominus

lsys_dominus    PROC
    cmp    reverse,0
    jnz    MinusDecAngle
    call    incangle
    ret
MinusDecAngle:
    call    decangle
    ret
lsys_dominus    ENDP

    PUBLIC    lsys_doplus_pow2

lsys_doplus_pow2    PROC
    mov    al,angle
    cmp    reverse,0
    jnz    Plus2IncAngle
    dec    al
    and    al,dmaxangle
    mov    angle,al
    ret
Plus2IncAngle:
    inc    al
    and    al,dmaxangle
    mov    angle,al
    ret
lsys_doplus_pow2    ENDP

    PUBLIC    lsys_dominus_pow2

lsys_dominus_pow2     PROC
    mov    al,angle
    cmp    reverse,0
    jz    Minus2IncAngle
    dec    al
    and    al,dmaxangle
    mov    angle,al
    ret
Minus2IncAngle:
    inc    al
    and    al,dmaxangle
    mov    angle,al
    ret
lsys_dominus_pow2     ENDP

    PUBLIC    lsys_dopipe_pow2

lsys_dopipe_pow2    PROC
    xor    ax,ax
    mov    al,maxangle
    shr    ax,1
    xor    dx,dx
    mov    dl,angle
    add    ax,dx
    and    al,dmaxangle
    mov    angle,al
    ret
lsys_dopipe_pow2    ENDP

    PUBLIC    lsys_dobang

lsys_dobang    PROC
    mov    al,reverse    ; reverse = ! reverse;
    dec    al        ; -1 if was 0; 0 if was 1
    neg    al        ; 1 if was 0; 0 if was 1
    mov    reverse,al    ;
    ret
lsys_dobang    ENDP

; Some 386-specific leaf functions go here.

.386

    PUBLIC    lsys_doslash_386

lsys_doslash_386    PROC    N:DWORD
    mov    eax,N
    cmp    reverse,0
    jnz    DoSlashDec
    add    realangle,eax
    ret
DoSlashDec:
    sub    realangle,eax
    ret
lsys_doslash_386    ENDP

    PUBLIC    lsys_dobslash_386

lsys_dobslash_386     PROC     N:DWORD
    mov    eax,N
    cmp    reverse,0
    jz    DoBSlashDec
    add    realangle,eax
    ret
DoBSlashDec:
    sub    realangle,eax
    ret
lsys_dobslash_386     ENDP

    PUBLIC    lsys_doat_386

lsys_doat_386    PROC    N:DWORD
    mov    eax,ssize    ; Get size
    imul    N        ; Mul by n
    shrd    eax,edx,19    ; Shift right 19 bits
    mov    ssize,eax    ; Save back
    ret
lsys_doat_386    ENDP

    PUBLIC    lsys_dosizegf_386

lsys_dosizegf_386    PROC
    mov    ecx,ssize    ; Get size; we'll need it twice
    xor    bx,bx        ; BX <- angle*sizeof(int)
    mov    bl,angle    ;
    shl    bx,1        ;
    shl    bx,1        ;
    mov    eax,coss[bx]    ; eax <- coss[angle]
    imul    ecx        ; Mul by size
    shrd    eax,edx,29    ; eax <- multiply(size, coss[angle], 29)
    add    eax,xpos    ;
    jno    nooverfl    ;   check for overflow
    mov    overflow,1    ;    oops - flag the user later
nooverfl:
    cmp    eax,lsys_Xmax    ; If xpos <= lsys_Xmax,
    jle    GF1        ;   jump
    mov    lsys_Xmax,eax    ;
GF1:    cmp    eax,lsys_Xmin    ; If xpos >= lsys_Xmin
    jge    GF2        ;   jump
    mov    lsys_Xmin,eax    ;
GF2:    mov    xpos,eax    ; Save xpos
    mov    eax,sins[bx]    ; eax <- sins[angle]
    imul    ecx        ;
    shrd    eax,edx,29    ;
    add    eax,ypos    ;
    cmp    eax,lsys_Ymax    ; If ypos <= lsys_Ymax,
    jle    GF3        ;   jump
    mov    lsys_Ymax,eax    ;
GF3:    cmp    eax,lsys_Ymin    ; If ypos >= lsys_Ymin
    jge    GF4        ;   jump
    mov    lsys_Ymin,eax    ;
GF4:    mov    ypos,eax    ;
    ret
lsys_dosizegf_386    ENDP

    PUBLIC    lsys_dodrawg_386

lsys_dodrawg_386    PROC
    mov    ecx,ssize    ; Because we need it twice
    xor    bx,bx        ; BX <- angle * sizeof(int)
    mov    bl,angle    ;
    shl    bx,1        ;
    shl    bx,1        ;
    mov    eax,coss[bx]    ; eax <- coss[angle]
    imul    ecx        ;
    shrd    eax,edx,29    ;
    add    xpos,eax    ; xpos += size*coss[angle] >> 29
    mov    eax,sins[bx]    ; eax <- sins[angle]
    imul    ecx        ; ypos += size*sins[angle] >> 29
    shrd    eax,edx,29    ;
    add    ypos,eax    ;
    ret            ;
lsys_dodrawg_386    ENDP

    END