Michael Webster Shell routine for TCB mfwebster@pdq.net 06-14-03 ( : ) TBC 187 4669 TBCSHELL.BAS* TBCSHELL.BAS is a TBC program that includes ă* a SHELL procedure and several related ă* procedures. ă* ă* Public Domain 2003 Michael Webster ă* : mfwebster@pdq.net ă* This was coded for the TOKIWA 8086 BASIC ă* compiler Ver. 5.55 *** Sample ***, ă* Copyright by Genjii OKADA. ă* ă* For testing, this program was compiled with ă* TBC TBCSHELL.BAS /A /O /#X for an EXE, and ă* TBC TBCSHELL.BAS /A /C /O /#X for a COM file. ă* ă* Likely error codes for the Load and Execute ă* Program function (Interrupt 21h, AX = 4B00h): ă* 0001h INVALID_FUNCTION ă* 0002h FILE_NOT_FOUND ă* 0003h PATH_NOT_FOUND ă* 0004h TOO_MANY_OPEN_FILES ă* 0005h ACCESS_DENIED ă* 0008h NOT_ENOUGH_MEMORY ă* 000Ah BAD_ENVIRONMENT ă* 000Bh BAD_FORMAT ă* If you fail to call FreeUnusedMemory first, ă* then the function will return error code 8. ă ă* These are global because I could find no ă* reasonable way to return a string from ă* a procedure. ăg_comspec$ = "" ăg_command$ = "" ă ă* This is global because it is accessed ă* from several procedures. ăinteger g_pspseg ă ă* This LOADEXEC structure is global because ă* I could not get LOC and OFFSET to work ă* correctly for local integers. ăinteger g_le_env ăinteger g_le_cmdoff ăinteger g_le_cmdseg ăinteger g_le_fcb1off ăinteger g_le_fcb1seg ăinteger g_le_fcb2off ăinteger g_le_fcb2seg ă ă*** Test code *** ă ăcall GetCommandLine ă*print g_command$ ăcall FreeUnusedMemory ăcall Shell(g_command$) ă*call Shell("mem /d/p") ă ă*** Procedures *** ă ăsubroutine InitPspSeg ă * Sets the global g_pspseg to the segment ă * address of the Program Segment Prefix. ă ă integer codeseg ă ă /mov ax,cs ă value = codeseg ă #c g_pspseg = codeseg ă #e g_pspseg = codeseg - 16 ă return ăsubend ă ăsubroutine InitComspec ă * Sets the global g_comspec$ to the value ă * of the COMSPEC environment variable. ă ă integer n, envseg ă character c ă ă call InitPspSeg ă envseg = dpeek(g_pspseg; &2c) ă n = 0 ă while peek(envseg; n) <> 0 ă g_comspec$ = "" ă while peek(envseg; n) <> 0 ă c = chr$(!) ă g_comspec$ = g_comspec$ + c ă n = n + 1 ă wend ă if instr(g_comspec$,"COMSPEC") = 1 then ă g_comspec$ = mid$(g_comspec$,instr(g_comspec$,"=") + 1) ă break ă endif ă n = n + 1 ă wend ă return ăsubend ă ăsubroutine GetCommandLine ă * Copies the program's command line to ă * the global g_command$. ă ă integer i, n ă character c ă ă call InitPspSeg ă ă g_command$ = "" ă ă n = peek(g_pspseg; &80) ă for i = &81 to n + &81 ă c = chr$(peek(g_pspseg; i)) ă g_command$ = g_command$ + c ă next i ă return ăsubend ă ăsubroutine FreeUnusedMemory ă * Resizes the program's memory block to ă * free unused memory above the program. ă ă integer stackseg, paragraphs ă ă call InitPspSeg ă /mov ax,ss ă value = stackseg ă paragraphs = stackseg + 4096 - g_pspseg ă /mov bx,paragraphs ă /mov ax,g_pspseg ă /mov es,ax ă /mov ax,&4a00 ă /int &21 ă /jnc @10 ă ă * Sophisticated error handling :) ă print ! ă10 return ăsubend ă ăsubroutine Shell(command$) ă * Starts a copy of the command processor and ă * passes it , formatted as a proper ă * command tail. ă ă integer g_comspec_off ă ă call InitPspSeg ă call InitComspec ă ă * This string must be initialized before ă * initializing LOADEXEC because TBC will ă * move it when it is initialized ! ă cmd_tail$ = " /C " ă cmd_tail$ = cmd_tail$ + command$ ă cmd_tail$ = chr$(len(cmd_tail$)) + cmd_tail$ + chr$(13) ă ă * Initialize LOADEXEC to use a copy of the ă * parent's environment and FCBs, and the ă * formatted command string. Note that the ă * storage order depends on the order in ă * which the variables are initialized rather ă * than the order in which they are declared. ă g_le_env = 0 ă g_le_cmdoff = dpeek(loc(cmd_tail$)) ă /mov ax,ds ă value = g_le_cmdseg ă g_le_fcb1off = &5c ă g_le_fcb1seg = g_pspseg ă g_le_fcb2off = &6c ă g_le_fcb1seg = g_pspseg ă ă g_comspec_off = dpeek(loc(g_comspec$)) ă ă /mov dx,g_comspec_off ă /push ds ă /pop es ă /mov bx,offset g_le_env ă /mov ax,bx ă /mov ax,&4b00 ă /int &21 ă /jnc @10 ă ă * Sophisticated error handling :) ă print ! ă10 return ăsubend ă ăend ăMichael Webster Free Unused Memory for TCB mfwebster@pdq.net 06-14-03 ( : ) TBC 34 891 MemFree.bas subroutine FreeUnusedMemory ă * Resizes the program's memory block to ă * free unused memory above the program. ă ă integer stackseg, extraseg, paragraphs ă ă call InitPspSeg ă /mov ax,ss ă value = stackseg ă /mov ax,es ă value = extraseg ă ă * If the value in ES is greater than the ă * value in SS, then at least one extended ă * array has been allocated. The value 4096 ă * assumes the maximum size (65536 bytes) ă * for the stack and extra segments. ă if extraseg > stackseg then ă paragraphs = extraseg + 4096 - g_pspseg ă else ă paragraphs = stackseg + 4096 - g_pspseg ă endif ă ă /mov bx,paragraphs ă /mov ax,g_pspseg ă /mov es,ax ă /mov ax,&4a00 ă /int &21 ă /jnc @10 ă ă * Sophisticated error handling :) ă print ! ă10 return ăsubend ă