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Assembly Source File | 1997-09-11 | 14.9 KB | 569 lines

; Small calculator for programmers. ; ALT-Z to pop up ; ; command line of form: <number> <operation> <number> Enter ; ; <number> is assumed to be decimal unless terminated with "H" ; <operation> can be "+-/*" ; ;---------------------------------------------------------------------------- debug equ 0 ;--------------------------------------------------------------------------- ; program equates ;--------------------------------------------------------------------------- window_start equ 80 dec_result_window equ 120 hex_result_window equ 142 window_size equ 40 window_color equ 70h ;---------------------------------------------------------------------------- ; Bios data in low ram ;---------------------------------------------------------------------------- bios_data segment at 40h org 17h bios_kbd_stat db ? org 4ah bios_crt_col dw ? org 63h addr_6845 dw ? org 84h bios_crt_row db ? bios_data ends ;---------------------------------------------------------------------------- ; PSP used as database for calculator to save space ;----------------------------------------------------------------------------- operation_type equ 7eh ;db- 0=none 1=add 2=sub 3=div 4=mul active equ 7fh ;db- 1=active base_flag equ 80h ;dw old_kbd_status equ 82h ;db- old_int_9h equ 83h ;dd- op1_base equ 87h ;db 0=no entry 10=decimal 16=hex op1_value equ 88h ;dd op2_base equ 8ch ;db 0=no entry 10=decimal 16=hex op2_value equ 8dh ;dd result equ 91h ;dd display_off_cur equ 95h ;dw-current display ptr display_segment equ 97h ;dw-display memory ptr op1_ascii equ 99h ;db(9) bcd followed by -1 op2_ascii equ 0a4h ;db(9) bck followed by -1 relocated_int09 equ 0b0h ;code is moved here ; ;--------------------------------------------------------------------------- ; code segment para public 'code' assume cs:code org 100h entry: jmp initialize ;------------------------------------------------------------------------------ ; Front-end routine for the keyboard interrupt handler. Execution is vectored ; here whenever an interrupt 9 us generated by the PC keyboard. ;------------------------------------------------------------------------------ int09_trap: assume cs:code,ds:code,es:nothing,ss:nothing cmp byte ptr cs:active,0 jne quick_out push ax in al,60h cmp al,2ch ;check for 'z' hot key jne out1 mov ah,2 int 16h ;get keyboard flags and al,0fh cmp al,8 ;check if alt key down jne out1 ;exit if no alt key jmp calculator out1: pop ax quick_out: jmp dword ptr cs:old_int_9h ;-------------------------------------------- calculator: push bx push cx push dx push si push di push ds push es mov ax,cs mov ds,ax ; ; KB_RESET resets the keyboard and signals end-of-interrupt to the 8259. ; in al,61h mov ah,al or al,80h out 61h,al mov al,ah out 61h,al cli mov al,20h out 20h,al mov byte ptr ds:active,1 sti mov word ptr ds:display_off_cur,window_start mov cx,window_size clear_window: mov al,' ' call display_char loop clear_window mov word ptr ds:display_off_cur,window_start ; The window is now displayed on the screen. Wait for a keypress. get_char_loop: mov ah,0 int 28h mov ah,1 int 16h jz get_char_loop mov ah,0 int 16h int095: cmp al,27 jne int09_cont1 ;jmp if not esc ; ; escape pressed ; done1: jmp done int09_cont1: cmp al,08 jne int09_cont2 ; rubout last char rubout: cmp word ptr ds:display_off_cur,window_start je get_char_loop sub word ptr ds:display_off_cur,2 mov al,' ' call display_char sub word ptr ds:display_off_cur,2 jmp get_char_loop done_error1: jmp done_error ; int09_cont2: cmp al,0dh je scan_data ;jmp if enter key call display_char jmp get_char_loop scan_data: call pre_scan jc done_error1 ; ; the data has been scanned and is ready for calculations ; convert both numbers to binary ; sub bh,bh mov bl,byte ptr ds:op1_base cmp bl,0 je done1 mov si,op1_ascii mov di,op1_value call ascii_to_binary jc done_error1 mov bl,byte ptr ds:op2_base cmp bl,0 je convert_only mov si,op2_ascii mov di,op2_value call ascii_to_binary ; ; both numbers are in binary at op1_value, op2_value ; Do operation requested. ; mov cl,byte ptr ds:operation_type mov ax,word ptr ds:op1_value mov dx,word ptr ds:op1_value+2 dec cx jcxz add_numbers dec cx jcxz subtract_numbers dec cx jcxz divide_numbers ; ; multiply - inputs: ds:si = dword 1 ds:di = dword2 ; mov bx,word ptr ds:op2_value call multiply ;result in dx,ax and ds:di jmp display_result ; ; add two values ; add_numbers: add ax,word ptr ds:op2_value adc dx,word ptr ds:op2_value+2 jmp display_result ; ; subtract two values ; subtract_numbers: sub ax,word ptr ds:op2_value sbb dx,word ptr ds:op2_value+2 jmp display_result ; ; divide two values - inputs: ds:si = dword1 ds:di = divisor (word) ; divide_numbers: cmp ax,0 jne dok1 cmp dx,0 je d_exit dok1: div word ptr ds:op2_value ;result in -ax- d_exit: sub dx,dx ;clear remainder jmp display_result ; ; only op1 was entered, move it to result and display ; convert_only: ; ; display result - dx,ax = result ; display_result: push ax push dx mov word ptr ds:base_flag,10 mov word ptr ds:display_off_cur,dec_result_window call display_number pop dx pop ax mov word ptr ds:base_flag,16 mov word ptr ds:display_off_cur,hex_result_window call display_number mov al,'H' call display_char done_error: done: mov byte ptr ds:active,0 pop es pop ds pop di pop si pop dx pop cx pop bx pop ax iret ;----------------------------------------------------------------------------- ; scan the entry line and parse to: ; op1_base - 0=not found 10=decimal 16=hex ; op1_ascii - bcd followed by -1 ; operation_type - 0=none 1=add 2=sub 3=div 4=mul ; op2_base - 0=not found 10=decimal 16=hex ; op2_ascii - bcd followed by -1 ; ; carry - set if error ; ; inputs: es: points at display ; ds: points at code segment ; pre_scan: mov si,window_start mov di,op1_ascii mov byte ptr ds:op1_base,0 mov byte ptr ds:op2_base,0 mov byte ptr ds:operation_type,0 ps_loop: mov ax,es:[si] ;get next char cmp al,' ' jne ps_cont1 ;jmp if more characters ; ; final character found ; mov al,'=' call display_char ; ; verify type code are set ; mov al,byte ptr ds:operation_type or al,byte ptr ds:op1_base jz set_op1_base cmp byte ptr ds:operation_type,0 je ps_exit1 ; ; an operator was found, so verify op2 type was found ; ;! mov byte ptr ds:[di],-1 ;terminate value2 cmp byte ptr ds:op2_base,0 jne ps_exit1 ;jmp if type set mov byte ptr ds:op2_base,10 ;set decimal type jmp ps_exit1 set_op1_base: mov byte ptr ds:op1_base,10 ps_exit1: mov byte ptr ds:[di],-1 clc jmp ps_exit ps_cont1: cmp al,'+' je plus_op cmp al,'-' je minus_op cmp al,'/' je divide_op cmp al,'*' je multiply_op cmp al,'h' je hex_entry cmp al,'H' je hex_entry cmp al,'0' jb ignore cmp al,'9' jbe got_numeric cmp al,'A' jb ignore cmp al,'F' jbe got_hex_numeric sub al,20h cmp al,'A' jb ignore cmp al,'F' jbe got_hex_numeric jmp ignore ignore: jmp bad_char got_numeric: jmp number_char got_hex_numeric:jmp hex_number_char plus_op: mov al,1 jmp stuff_operation minus_op: mov al,2 jmp stuff_operation divide_op: mov al,3 jmp stuff_operation multiply_op: mov al,4 stuff_operation:mov byte ptr ds:operation_type,al mov byte ptr ds:[di],-1 ;terminate op1 mov di,op2_ascii cmp byte ptr ds:op1_base,0 jne nxt_char2 ;jmp if type known mov byte ptr ds:op1_base,10 ;decimal type jmp nxt_char2 hex_entry: cmp byte ptr ds:op1_base,0 je this_is_op1 mov byte ptr ds:op2_base,16 jmp nxt_char2 this_is_op1: mov byte ptr ds:op1_base,16 jmp nxt_char2 number_char: sub al,'0' jmp nxt_char1 hex_number_char:sub al,('A'-10) nxt_char1: mov byte ptr ds:[di],al inc di nxt_char2: add si,2 jmp ps_loop bad_char: stc ps_exit: ret ;----------------------------------------------------------------------------- ; display character ; inputs: al = char ; display_char: push di cld mov ah,window_color ;get attribute les di,dword ptr ds:display_off_cur ;get display point stosw mov word ptr ds:display_off_cur,di pop di ret ;----------------------------------------------------------------------------- ; convert ascii string to binary ; inputs ds:si numeric string ; bx = base ; ds:di = result storage area ; output ; si = updated to point at end of value ; carry set if error ; ascii_to_binary: sub dx,dx ;clear high accumulator sub ax,ax ;clear low accumulator jmp ab2 ab_loop: inc si ;move to next char ab2: mov cl,[si] cmp cl,-1 je ab_done ;jmp if done cmp cl,bl ja ab_err ;jmp if char. out of range sub ch,ch ; ; multiply sum by current base ; call multiply ;dx,ax * bx ; ; add latest character to sum ; add ax,cx ;add to sum adc dx,0 ;add carry jmp ab_loop ab_done: clc mov word ptr ds:[di],ax mov word ptr ds:[di+2],dx jmp ab_exit ab_err: stc ab_exit: ret ;----------------------------------------------------------------------------- ; inputs: dx,ax = binary value ; outputs: none ; ; registers destroyed: ax,dx ; display_number: push ax mov ax,dx xor dx,dx div word ptr ds:base_flag mov bx,ax pop ax div word ptr ds:base_flag xchg bx,dx ; ; dx,ax = quotient ; bx = remainder or ax,ax jnz dd_more or dx,dx jnz dd_more mov dx,bx jmp ddb_display dd_more: push bx ;save remainder call display_number ;recursion pop dx ddb_display: add dl,30h ;convert char. to ascii cmp dl,'9' jbe dd_dsp add dl,('A'-'9'-1) dd_dsp: push ax mov al,dl call display_char pop ax ret ;--------------------------------------------------------------------------- ; multiply two numbers ; inputs: dx,ax * bx ; output: dx,ax is updated ; result to [di] also ; multiply: push ax mov ax,dx mul bx mov word ptr ds:[di+2],ax pop ax mul bx add word ptr ds:[di+2],dx mov word ptr ds:[di],ax mov dx,word ptr ds:[di+2] ret ;--------------------------------------------------------------------------- ;! db 8 dup (0) ;------------------------------------------------------------------------------ ; INITIALIZE redirects the keyboard interrupt, then reserves enough memory for ; the program to remain resident. ;------------------------------------------------------------------------------ initialize: ; determine location of display segment mov ah,15 int 10h mov bx,0b000h ;preload mda cmp al,7 je stuff_vseg mov bx,0b800h stuff_vseg: mov word ptr ds:[display_segment],bx mov word ptr ds:base_flag,10 ;decimal mov byte ptr ds:op1_base,0 mov word ptr ds:op1_value,0 mov word ptr ds:op1_value+2,0 mov byte ptr ds:op2_base,0 mov word ptr ds:op2_value,0 mov word ptr ds:op2_value+2,0 mov word ptr ds:result,0 mov word ptr ds:result+2,0 mov byte ptr ds:operation_type,0 mov word ptr ds:display_off_cur,window_start mov byte ptr ds:active,0 mov dx,offset program mov ah,9 int 21h if debug jmp calculator endif ; ; move code up into psp ; mov si,offset int09_trap mov di,relocated_int09 mov cx,(offset initialize -103h) cld rep movsb mov cx,50h mov al,0 rep stosb ;clear end of program no_copies: mov ah,35h mov al,9 int 21h mov word ptr ds:old_int_9h,bx mov word ptr ds:old_int_9h+2,es mov ah,25h mov al,9 mov dx,relocated_int09 ;offset int09_trap int 21h ; Exit by TSR int 31h. mov dx,offset initialize sub dx,050h-15 mov cl,4 shr dx,cl mov ax,3100h int 21h program db 0dh,0ah db '┌────────────────────────────────────────────────────────────────────────┐',0dh,0ah db '│ CALC (small programmers calculator) ** ALT-Z ** for each calculation │',0dh,0ah db '│ │',0dh,0ah db '│ Usage: <number> <operator> <number> Enter │',0dh,0ah db '│ │',0dh,0ah db '│ <number> decimal or hex number, hex numbers of form nnnnH │',0dh,0ah db '│ <operator> any of the following + - / * Enter │',0dh,0ah db '│ │',0dh,0ah db '│ Released to public domain by Jeff Owens, Estacada, Oregon │',0dh,0ah db '└────────────────────────────────────────────────────────────────────────┘',0dh,0ah db 0dh,0ah,'$' code ends end entry