* * System0.asm - invoke system's command processor * * Copyright (C) by Ralph Babel, Guru Meditation Network, * Falkenweg 3, D-6204 Taunusstein, West-Germany * * This piece of code may be used as part of any product as * long as the source code for the complete program can be * obtained free of charge (except for a small copying fee) * and this copyright notice is left unchanged. * * Bug reports and improved versions appreciated. * * 20-Jul-1987 created original version * 11-Jan-1988 now based on "official" information only * 9-Apr-1990 modified heavily by Lionel Hummel for PDC release 3.3 * include "exec/types.i" include "libraries/dos.i" include "libraries/dosextens.i" * * LONG System0(name, seglist, args) * char *name; * BPTR seglist; * char *args; * xdef _System0 xref _DOSBase AbsExecBase equ 4 xref _LVOFindTask xref _LVOAllocMem xref _LVOSetSignal xref _LVOFreeMem xref _ReportSL * parameter offsets & stack SAVED_REGS reg a2-a6/d2-d7 DELTA equ 11*4 ARG_NAME equ 4+DELTA ARG_SEGLIST equ 8+DELTA ARG_ARGS equ 12+DELTA * additional return codes NO_CLI equ -1 NO_MEM equ -2 * local constants MAXBSTR equ 255 LF equ 10 * register usage REG_Result equr d3 REG_Process equr a2 ;may not be A4, see below! REG_CLI equr a3 REG_CIS equr a4 ;may not be A3, see below! REG_PrevStack equr a5 REG_SysBase equr a6 * local stack frame STRUCTURE StackFrame,0 STRUCT sf_CommandName,MAXBSTR+1 ;BSTR, length byte! APTR sf_PrevStack APTR sf_SaveReturnAddr BPTR sf_SaveModule BPTR sf_SaveCommandName APTR sf_StackBase LONG sf_StackSize LONG sf_PushSize APTR sf_Process APTR sf_CLI APTR sf_CIS BPTR sf_SCB_Buf LONG sf_SCB_Pos LONG sf_SCB_End LABEL sf_SIZEOF * entry point _System0: movem.l SAVED_REGS,-(sp) moveq #NO_CLI,REG_Result ;ERROR - not a CLI task movea.l AbsExecBase,REG_SysBase suba.l a1,a1 jsr _LVOFindTask(REG_SysBase) movea.l d0,REG_Process move.l pr_CLI(REG_Process),d0 beq quit0 * build local stack frame & save some values lsl.l #2,d0 ;BPTR to machine pointer movea.l d0,REG_CLI movea.l sp,REG_PrevStack ;save old stack pointer move.l sp,d0 andi.b #$fc,d0 ;make SP longword-aligned for BPTRs movea.l d0,sp suba.w #sf_SIZEOF,sp move.l REG_PrevStack,sf_PrevStack(sp) move.l REG_Process,sf_Process(sp) move.l REG_CLI,sf_CLI(sp) move.l pr_ReturnAddr(REG_Process),sf_SaveReturnAddr(sp) * allocate space for stack moveq #NO_MEM,REG_Result ;ERROR - no memory for STACK move.l cli_DefaultStack(REG_CLI),d0 ;in longwords for "VEC" lsl.l #2,d0 move.l d0,sf_PushSize(sp) addq.l #4,d0 ;one additional longword move.l d0,sf_StackSize(sp) moveq #0,d1 ;intentionally NOT "MEMF_PUBLIC"! jsr _LVOAllocMem(REG_SysBase) tst.l d0 beq quit1 move.l d0,sf_StackBase(sp) ;save result * save old command pointer, build new BCPL command name move.l cli_CommandName(REG_CLI),sf_SaveCommandName(sp) movea.l ARG_NAME(REG_PrevStack),a0 ;first parameter to "System0()" lea sf_CommandName+1(sp),a1 ;first char location for BSTR move.l a1,d0 lsr.l #2,d0 ;will ignore (+1), BPTR as result move.l d0,cli_CommandName(REG_CLI) move.w #MAXBSTR,d0 bra.s L2 L1 move.b d1,(a1)+ L2 move.b (a0)+,d1 dbeq d0,L1 suba.l ARG_NAME(REG_PrevStack),a0 ;subtract original source move.l a0,d0 subq.l #1,d0 ;terminating null-byte move.b d0,sf_CommandName(sp) ;to first location in BSTR * save contents of Current Input Stream move.l pr_CIS(REG_Process),d0 lsl.l #2,d0 movea.l d0,REG_CIS ;contains APTR to CIS move.l REG_CIS,sf_CIS(sp) move.l fh_Buf(REG_CIS),sf_SCB_Buf(sp) move.l fh_Pos(REG_CIS),sf_SCB_Pos(sp) move.l fh_End(REG_CIS),sf_SCB_End(sp) * setup start/end indices in Stream Control Block move.l ARG_ARGS(REG_PrevStack),a0 ; LW aligned by system() move.l a0,d0 lsr.l #2,d0 ;make buffer pointer a BPTR move.l d0,fh_Buf(REG_CIS) move.l #0,d0 bra.s L4 L3 addq.l #1,d0 L4 move.b (a0)+,d1 bne L3 move.l d0,fh_End(REG_CIS) clr.l fh_Pos(REG_CIS) * misc setup clr.l pr_Result2(REG_Process) ;clear secondary result moveq #0,d0 move.l #SIGBREAKF_CTRL_C,d1 jsr _LVOSetSignal(REG_SysBase) * handle seglist and start address move.l cli_Module(REG_CLI),sf_SaveModule(sp) move.l ARG_SEGLIST(REG_PrevStack),d0 ;second argument to "System0()" move.l d0,cli_Module(REG_CLI) lsl.l #2,d0 movea.l d0,a3 ;make it a machine pointer in A3 * setup processor registers & C-interface move.l ARG_ARGS(REG_PrevStack),a0 move.l fh_End(REG_CIS),d0 * setup processor registers, BCPL-interface, stack & return address for "Exit()" movea.l sf_StackBase(sp),a1 ;BCPL stack, low end move.l sf_PushSize(sp),d2 lea 4(a1,d2.l),a4 ;must not destroy REG_Process! move.l sp,-(a4) ;previous stack frame move.l d2,-(a4) ;stack size in bytes move.l a4,pr_ReturnAddr(REG_Process) movea.l a4,sp movea.l _DOSBase,a4 ;large data memory model! movem.l dl_A2(a4),a2/a5/a6 * now call the command at its entry point jsr 4(a3) ;code starts one longword behind segment pointer move.l d0,REG_Result ;save return code * get old stackframe & reload old register contents movea.l 4(sp),sp ;old stack frame movea.l sf_Process(sp),a0 move.l sf_SaveReturnAddr(sp),pr_ReturnAddr(a0) movea.l sf_CLI(sp),a0 move.l sf_SaveCommandName(sp),cli_CommandName(a0) move.l sf_SaveModule(sp),cli_Module(a0) * restore original contents of Current Input Stream movea.l sf_CIS(sp),a0 move.l sf_SCB_Buf(sp),fh_Buf(a0) move.l sf_SCB_Pos(sp),fh_Pos(a0) move.l sf_SCB_End(sp),fh_End(a0) * free temporary stack movea.l AbsExecBase,REG_SysBase movea.l sf_StackBase(sp),a1 move.l sf_StackSize(sp),d0 jsr _LVOFreeMem(REG_SysBase) quit1 movea.l sf_PrevStack(sp),sp ;UNLINK local variables quit0 move.l REG_Result,d0 movem.l (sp)+,SAVED_REGS rts end