Microsoft Programmer's Library 1.3

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Assembly Source File | 1988-12-12 | 11.6 KB | 318 lines

title TINYCMD -- Simple Command Interpreter page 55,132 .286 ; ; TINYCMD.ASM ; ; A simple command interpreter for OS/2. ; ; Assemble with: C> masm tinycmd.asm; ; Link with: C> link tinycmd,,,os2,tinycmd ; ; Usage is: C> tinycmd ; ; Copyright (C) 1988 Ray Duncan ; cr equ 0dh ; ASCII carriage return lf equ 0ah ; ASCII linefeed tab equ 09h ; ASCII tab blank equ 20h ; ASCII blank code escape equ 01bh ; ASCII escape code inpsize equ 80 ; maximum input length extrn DosExecPgm:far ; OS/2 API functions extrn DosExit:far extrn DosGetVersion:far extrn KbdStringIn:far extrn VioWrtTTY:far DGROUP group _DATA _DATA segment word public 'DATA' ; Intrinsic commands table: Each entry is an ASCIIZ string ; followed by the offset of the corresponding procedure. commands label byte db 'CLS',0 ; clear screen command dw cls_cmd db 'VER',0 ; display OS/2 version dw ver_cmd db 'EXIT',0 ; exit from TINYCMD dw exit_cmd db 0 ; end of table input db (inpsize+2) dup (0) ; keyboard input buffer ibinfo dw inpsize,0 ; input buffer info pbuff db (inpsize+2) dup (0) ; program name moved here cinfo dw 0 ; child termination type dw 0 ; child return code prompt db cr,lf,'>> ' ; TINYCMD's user prompt pr_len equ $-prompt delims db 0,blank,tab,';,=' ; delimiters for first de_len equ $-delims ; command line token pext db '.EXE',0 ; program file extension pe_len equ $-pext wlen dw 0 ; receives bytes written verinfo db 0,0 ; receives OS/2 version msg1 db cr,lf,lf ; error message db 'Bad command or filename' db cr,lf msg1_len equ $-msg1 msg2 db escape,'[2J' ; ANSI escape sequence msg2_len equ $-msg2 ; to clear the screen msg3 db cr,lf,lf ; version number message db 'OS/2 version ' msg3a db 'nn.' msg3b db 'nn' db cr,lf msg3_len equ $-msg3 _DATA ends _TEXT segment word public 'CODE' assume cs:_TEXT,ds:DGROUP,es:DGROUP main proc far ; entry point from OS/2 push ds ; make DGROUP addressable pop es ; with ES too cld ; clear direction flag main1: ; main interpreter loop call gcmd ; get command from user call intrinsic ; check if intrinsic function jnc main1 ; yes, it was processed call extrinsic ; no, run EXE file, then jmp main1 ; get another command main endp ; Try to match first command token against COMMANDS table. ; If match, run the routine, return Carry = False. ; If no match, return Carry = True. intrinsic proc near ; point to command table mov si,offset DGROUP:commands intr1: ; try next table entry... cmp byte ptr [si],0 ; end of entire table? je intr6 ; jump if table exhausted mov di,offset DGROUP:input ; point to user's command intr2: mov al,[si] ; next character from table or al,al ; end of table entry? jz intr3 ; yes, jump cmp al,[di] ; compare to input character jnz intr4 ; jump, found mismatch inc si ; advance string pointers inc di jmp intr2 intr3: cmp byte ptr [di],0 ; user's entry same length? jne intr5 ; no, not a match call word ptr [si+1] ; run the command routine clc ; return Carry = False ret ; as success signal intr4: lodsb ; look for end of this or al,al ; command string (null byte) jnz intr4 ; not end yet, loop intr5: add si,2 ; skip over routine address jmp intr1 ; try to match next command intr6: stc ; command not matched, exit ret ; with Carry = True intrinsic endp ; Append .EXE to first token and attempt to execute program, ; passing address of argument strings block and null pointer ; for environment (child process inherits TINYCMD's environment). extrinsic proc near mov si,offset DGROUP:input ; copy first token of mov di,offset DGROUP:pbuff ; user command to pbuff extr1: lodsb ; get next character or al,al ; found null? jz extr2 ; yes, end of token stosb ; no, copy character jmp extr1 ; and get next char. extr2: mov si,offset DGROUP:pext ; append .EXE extension mov cx,pe_len ; to token, forming rep movsb ; program filename ; try and run program... push 0 ; object name buffer push 0 push 0 ; object name buffer length push 0 ; asynchronous execution mode push ds ; address of argument strings push offset DGROUP:input push 0 ; environment pointer push 0 push ds ; receives termination info push offset DGROUP:cinfo push ds ; address of program name push offset DGROUP:pbuff call DosExecPgm ; transfer to OS/2 or ax,ax ; was function successful? jz extr3 ; yes, jump ; no, display error message... push ds ; message address push offset DGROUP:msg1 push msg1_len ; message length push 0 ; default video handle call VioWrtTTY ; transfer to OS/2 extr3: ret ; back to caller extrinsic endp ; Get input from user, convert it to argument strings block ; by breaking out first token with null and appending double ; null to entire line, and convert first token to uppercase. gcmd proc near ; prompt user, get command ; display TINYCMD prompt... push ds ; address of prompt push offset DGROUP:prompt push pr_len ; length of prompt push 0 ; default video handle call VioWrtTTY mov ibinfo+2,0 ; disable buffer editing ; get entry from user... push ds ; address of input buffer push offset DGROUP:input push ds ; input buffer info push offset DGROUP:ibinfo push 0 ; 0 = wait for input push 0 ; default keyboard handle call KbdStringIn mov cx,inpsize ; look for carriage return mov al,cr ; if any... mov di,offset DGROUP:input repnz scasb jnz gcmd1 dec di gcmd1: mov word ptr [di],0 ; and replace with 2 nulls mov si,offset DGROUP:input ; break out first token... gcmd2: lodsb ; compare next character mov di,offset DGROUP:delims ; to delimiter table mov cx,de_len repnz scasb jnz gcmd2 ; jump, no match mov byte ptr [si-1],0 ; replace delimiter with 0 mov si,offset DGROUP:input ; fold token to uppercase gcmd3: cmp byte ptr [si],0 ; end of token? jz gcmd5 ; found end, jump cmp byte ptr [si],'a' jb gcmd4 ; jump if not 'a-z' cmp byte ptr [si],'z' ja gcmd4 ; jump if not 'a-z' sub byte ptr [si],'a'-'A' ; convert to uppercase gcmd4: inc si ; go to next character jmp gcmd3 gcmd5: ret ; back to caller gcmd endp cls_cmd proc near ; intrinsic CLS command ; send ANSI escape sequence ; to clear the screen... push ds ; escape sequence address push offset DGROUP:msg2 push msg2_len ; escape sequence length push 0 ; default video handle call VioWrtTTY ; transfer to OS/2 ret ; back to caller cls_cmd endp ver_cmd proc near ; intrinsic VER command ; get OS/2 version number... push ds ; receives version info push offset DGROUP:verinfo call DosGetVersion ; transfer to OS/2 ; format the version... mov al,verinfo ; convert minor version aam ; number to ASCII add ax,'00' xchg al,ah mov word ptr msg3b,ax ; store ASCII characters mov al,verinfo+1 ; convert major version aam ; number to ASCII add ax,'00' xchg al,ah mov word ptr msg3a,ax ; store ASCII characters ; display version number... push ds ; message address push offset DGROUP:msg3 push msg3_len ; message length push 0 ; default video handle call VioWrtTTY ; transfer to OS/2 ret ; back to caller ver_cmd endp exit_cmd proc near ; intrinsic EXIT Command ; final exit to OS/2... push 1 ; terminate all threads push 0 ; return code = 0 call DosExit ; transfer to OS/2 exit_cmd endp _TEXT ends end main ; defines entry point