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Text File | 1989-07-11 | 11.7 KB | 278 lines

; Micro Cornucopia Magazine Issue #49 ; PostScriptals article code ; ; This is a pruned version of Harlan Stockman's 386 specific code originally ; run in Micro Cornucopia Issue #43. I used it for the PostScriptal article ; in Issue #49. The code that's left has not been altered - I just removed ; the stuff I didn't need and reassembled with DeSmet. ; Larry Fogg - June 28, 1989 ; This file is mand.a ... DeSmet asm88 functions for fr386.c, ; a fixed-pt 386 version of Mandelbrot ... ; mandwhile.a replaces inner "while" loop of mandelbrot calculation... ;==============386-SPECIFIC FUNCTIONS=================================== ; int mandwhile(long P, long Q, int nmax) ; Performs all calculations for "while" loop in L.Fogg's mandel() ; function, using fixed pt math with binary pt between bits 23 and 24... ; ; FOR: DeSmet C/asm88 small case... ; ; In REAL MODE; uses 32-bit overrides on register length and addressing to ; gain performance of 32-bit regs and instructions... ; Returns # iterations before divergence (16-bit int returned in ax). ; Note 1/3 rd of instructions are for rounding, to get small amount extra ; accuracy; if you aren't that picky, dump these instructions for 10% or more ; extra speed... ; ; REGISTERS: ebp ...ytemp at top of loop, modulus_sqrd ; at bottom of loop ; edx:eax ...multiplication and temporary storage ; edi ...P ; esi ...Q ; ebx ...x ; ecx ...y ; ; RETURNS stopping number of iterations in ax. dseg public counter counter dw 0 cseg public mandwhile_ mandwhile_: db 66h, 55h ;push ebp ;---get P ... db 67h, 66h, 8Bh, 7Ch, 24h, 06h ;mov edi,dword [esp+6] ;---get Q ... db 67h, 66h, 8Bh, 74h, 24h, 0Ah ;mov esi,dword [esp+10] ;---get nmax... db 67h, 8Bh, 44h, 24h, 0Eh ;mov ax,word [esp+14] ;---initialize counter ... mov word counter,ax ;---zero out x and y storage ... db 66h, 33h, 0DBh ;xor ebx,ebx db 66h, 33h, 0C9h ;xor ecx,ecx looper: ;---ytemp=x*y--- db 66h, 8Bh, 0C3h ;mov eax,ebx db 66h, 0F7h, 0E9h ;imul ecx db 66h, 05h, 00h, 00h, 80h, 00h ;add eax,800000H ;for rounding... db 66h, 83h, 0D2h, 00h ;adc edx,0 ;for rounding... db 66h, 0Fh, 0A4h, 0C2h, 08h ;shld edx,eax,8 ;div by 2**24... db 66h, 8Bh, 0EAh ;mov ebp,edx ;---x=x*x - y*y + P------ db 66h, 8Bh, 0C3h ;mov eax,ebx db 66h, 0F7h, 0EBh ;imul ebx db 66h, 05h, 00h, 00h, 80h, 00h ;add eax,800000H db 66h, 83h, 0D2h, 00h ;adc edx,0 db 66h, 0Fh, 0A4h, 0C2h, 08h ;shld edx,eax,8 db 66h, 8Bh, 0DAh ;mov ebx,edx ;--- db 66h, 8Bh, 0C1h ;mov eax,ecx db 66h, 0F7h, 0E9h ;imul ecx db 66h, 05h, 00h, 00h, 80h, 00h ;add eax,800000H db 66h, 83h, 0D2h, 00h ;adc edx,0 db 66h, 0Fh, 0A4h, 0C2h, 08h ;shld edx,eax,8 db 66h, 2Bh, 0DAh ;sub ebx,edx db 66h, 03h, 0DFh ;add ebx,edi ;add P... ;---y=(ytemp<<1) + Q---- db 66h, 0D1h, 0E5h ;shl ebp,1 db 66h, 03h, 0EEh ;add ebp,esi ;add Q... db 66h, 8Bh, 0CDh ;mov ecx,ebp ;---modsqrd = x*x + y*y--- db 66h, 8Bh, 0C3h ;mov eax,ebx db 66h, 0F7h, 0EBh ;imul ebx db 66h, 05h, 00h, 00h, 80h, 00h ;add eax,800000H db 66h, 83h, 0D2h, 00h ;adc edx,0 db 66h, 0Fh, 0A4h, 0C2h, 08h ;shld edx,eax,8 db 66h, 8Bh, 0EAh ;mov ebp,edx ;--- db 66h, 8Bh, 0C1h ;mov eax,ecx db 66h, 0F7h, 0E9h ;imul ecx db 66h, 05h, 00h, 00h, 80h, 00h ;add eax,800000H db 66h, 83h, 0D2h, 00h ;adc edx,0 db 66h, 0Fh, 0A4h, 0C2h, 08h ;shld edx,eax,8 db 66h, 03h, 0EAh ;add ebp,edx ;---test if modsqrd > "4"---(67108864 = 4*(1 << 24))--- db 66h, 81h, 0FDh, 00h,00h,00h,04h ;cmp ebp,67108864 jae home dec word counter jnz looper home: mov ax,word counter neg ax db 67h, 03h, 44h, 24h, 0Eh ;add ax, word [esp+14] db 66h, 5Dh ;pop ebp ret ; long muldiv(long A, int b, int c) ; Multiplies 32-bit "a" by 16-bit "b", then divides by ; 16-bit "c" such that abs(c) >= abs(b)...NO CHECK FOR 0 DIVISOR... ; ; NOTE how DeSmet figures stack upon entry: ; 16-bit return address at sp, "A" at sp+2, b at sp+6, c at sp+8 ... ; ; REGISTERS: eax ...initially holds "A" ; ebx ...holds b ; ecx ...holds c ; edx:eax ...product A*b (before idiv) ; ; RETURNS long result in dx:ax. cseg public muldiv_ muldiv_: db 67h,66h,8bh,44h,24h,02h ;mov eax,dword ptr [esp+2] db 67h,66h,0fh,0bfh,5ch,24h,06h ;movsx ebx,word ptr [esp+6] db 67h,66h,0fh,0bfh,4ch,24h,08h ;movsx ecx,word ptr [esp+8] db 66h,0f7h,0ebh ;imul ebx db 66h,0f7h,0f9h ;idiv ecx db 66h,0fh,0a4h,0c2h,10h ;shld edx,eax,16 ret ;short return... ;==============TEST FOR 386=============================== ; int is_386() ; 2-20-88 checks for presence of 386 -- returns 0 if not found, else ; returns non-zero ... ; note short return for DeSmet asm88 small case ... ; REF: Juan E. Jimenez, Turbo Technix Jan/Feb 88, p. 55 ... cseg public is_386_ is_386_: pop di ;return address ... pushf xor ax,ax push ax popf pushf pop ax and ax,8000h sub ax,8000h jz home2 ;------ mov ax,7000h ;if here, either 286 or 386 ... push ax popf pushf pop ax and ax,7000h home2: jmp di ;==============DESMET KEYBOARD POLLING ROUTINES=========== ; int scr_ci() and int scr_csts() ; These functions read the keyboard; scr_ci() waits until ; a key is typed, and returns the key; scr_csts() does not wait and returns ; 0 if no key is available. Unlike DeSmet functions ci() and csts(), these ; functions can read and translate extended keyboard codes (e.g., cursors ; and function keys). NOTE these are slightly faster than scr_ci() and ; scr_csts() given in DeSmet's optional PCIO.a file . ; ; FOR TURBO C: replace with combination of kbhit() and getch()... dseg ; TABLES to convert (scan_code - 59) to char code... table1: db 210 ;F1 scan= 59 db 211 ;F2 60 db 212 ;F3 61 db 213 ;F4 62 db 214 ;F5 63 db 215 ;F6 64 db 216 ;F7 65 db 217 ;F8 66 db 218 ;F9 67 db 219 ;F10 68 db 0 ;NumLock 69 ...not used db 0 ;ScrollL 70 ...not used db 200 ;bol_char 71 db 30 ;up_arrow 72 db 202 ;page_up 73 db 0 ;grey(-) 74 ...not used db 29 ;left_arrow 75 db 0 ;NumPad5 76 ...not used db 28 ;right_arrow77 db 0 ; 78 ...not used db 201 ;eol_char 79 db 31 ;down_arrow 80 db 203 ;page_down 81 db 206 ;Insert 82 db 207 ;Delete 83 public table2 table2: db 209 ;left_word 115 db 208 ;right_word 116 db 205 ;end_of_file117 db 0 ; 118 ..not used db 204 ;begin_file 119 cseg public scr_ci_ scr_ci_: push bp mov ah,0 int 16H cmp al,0 jne not_special mov bl,ah xor bh,bh cmp bx,114 ja use_table2 sub bx,59 mov al,byte table1[bx] jmp not_special use_table2: sub bx,115 mov al,byte table2[bx] not_special: xor ah,ah pop bp ret public scr_csts_ scr_csts_: push bp mov ah,1 int 16H mov ax,0 jz csts_over call scr_ci_ csts_over: pop bp ret ;==============LOG COLOR TRANSFORM=================================== ; 2-20-88 transform(int iter, int switchpt) ... DeSmet asm88 ... ; for frac386.c ... ; ...returns the "color" then anded with (maxcolors-1)... ; converts the iterations returned by mand() to a log scaling, starting at ; the switchpt. Equiv. to C coding: ; if(iter < switchpt) color = iter; ; else for(color=i=switchpt,inc=1; i<iter; i=switchpt+(inc<<=1),color++); ; ...However, 386 is so fast we need to translate to asm to get full benefit! cseg public transform_ transform_: pop di ;return address... pop cx ;iter... pop bx ;switchpt... sub sp,4 ;required by DeSmet for short return... cmp cx,bx ja do_loop mov ax,cx jmp di ;short return... ;------ do_loop: mov ax,bx ;init color (ax) with switchpt... mov si,2 ;si = inc... (originally = 1) mov dx,bx ;init i (dx) with switchpt... ;------ loopit: cmp dx,cx ;compare i (dx) to iter (cx)... jge done shl si,1 ;inc <<= 1... mov dx,bx add dx,si ;i = switchpt + inc... inc ax jmp loopit ;------ done: jmp di ;short return, color in ax...