--- /dev/null
+/*
+ * COPYRIGHT: GPL - See COPYING in the top level directory
+ * PROJECT: ReactOS Virtual DOS Machine
+ * FILE: command.S
+ * PURPOSE: DOS32 command.com for NTVDM
+ * PROGRAMMERS: Hermes Belusca-Maito (hermes.belusca@sfr.fr)
+ */
+
+//
+// See http://www.ganino.com/games/scripts/dos-6.0%20source%20code%3F/dev/smartdrv/umbload.asm
+// and https://books.google.fr/books?id=rtmJgtfaxz8C&pg=PA256&lpg=PA256&dq=int+21+4b+program+exec+block&source=bl&ots=OfAF7qFwfl&sig=PrW73CE1dzFm3rwrTsYZkC77U4Y&hl=en&sa=X&redir_esc=y#v=onepage&q=int%2021%204b%20program%20exec%20block&f=false
+//
+
+/* INCLUDES *******************************************************************/
+
+#include <asm.inc>
+#include "asmxtras.inc"
+#include <isvbop.inc>
+
+#define NDEBUG
+
+/* DEFINES ********************************************************************/
+
+#define MAX_PATH 260
+#define DOS_CMDLINE_LENGTH 127
+
+#define DOS_VERSION HEX(0005) // MAKEWORD(5, 00)
+#define NTDOS_VERSION HEX(3205) // MAKEWORD(5, 50)
+
+#define SYSTEM_PSP HEX(08)
+
+#define BOP .byte HEX(C4), HEX(C4),
+// #define BOP_START_DOS HEX(2C)
+#define BOP_CMD HEX(54)
+
+/**** PSP MEMBERS ****/
+#define PSP_VAR(x) es:[x]
+#define PSP HEX(0000)
+#define ParentPsp HEX(0016) // word
+#define EnvBlock HEX(002C) // word
+#define CmdLineLen HEX(0080) // byte
+#define CmdLineStr HEX(0081) // byte[DOS_CMDLINE_LENGTH]
+
+/**** DATA stored inside the stack ****/
+#define CmdLine BaseStack // Command line for the program to be started
+#define PgmName [CmdLine + (1 + DOS_CMDLINE_LENGTH)]
+
+
+// WARNING! Using the VAL(x) macro doesn't work with GCC/GAS (because it inserts
+// a spurious space in front of the parameter when the macro is expanded).
+// So that: 'VAL(foo)' is expanded to: '\ foo', instead of '\foo' as one would expect.
+
+/* NEXT_CMD structure */
+STRUCT(NEXT_CMD, 2)
+ FIELD_DECL(EnvBlockSeg, word, 0)
+ FIELD_DECL(EnvBlockLen, word, 0)
+ FIELD_DECL(CurDrive , word, 0)
+ FIELD_DECL(NumDrives , word, 1)
+ FIELD_DECL(CmdLineSeg , word, 0)
+ FIELD_DECL(CmdLineOff , word, 0)
+ FIELD_DECL(Unknown0 , word, 2)
+ FIELD_DECL(ExitCode , word, 3)
+ FIELD_DECL(Unknown1 , word, 4)
+ FIELD_DECL(Unknown2 , long, 5)
+ FIELD_DECL(CodePage , word, 6)
+ FIELD_DECL(Unknown3 , word, 7)
+ FIELD_DECL(Unknown4 , word, 8)
+ FIELD_DECL(AppNameSeg , word, 0)
+ FIELD_DECL(AppNameOff , word, 0)
+ FIELD_DECL(AppNameLen , word, 0)
+ FIELD_DECL(Flags , word, 0)
+ENDS(NEXT_CMD)
+
+/* DOS_EXEC_PARAM_BLOCK structure */
+STRUCT(DOS_EXEC_PARAM_BLOCK, 2)
+ FIELD_DECL(EnvSeg, word, 0) // Use parent's environment (ours)
+ FIELD_DECL(CmdLineOff, word, OFF(CmdLine))
+ FIELD_DECL(CmdLineSeg, word, 0)
+ FIELD_DECL(Fcb1Off, word, OFF(Fcb1))
+ FIELD_DECL(Fcb1Seg, word, 0)
+ FIELD_DECL(Fcb2Off, word, OFF(Fcb2))
+ FIELD_DECL(Fcb2Seg, word, 0)
+ENDS(DOS_EXEC_PARAM_BLOCK)
+
+
+
+/* RESIDENT CODE AND DATA *****************************************************/
+
+.code16
+// .org HEX(0100)
+ASSUME CS:.text, DS:.text, ES:.text
+
+
+/* CODE *******************************/
+
+EntryPoint:
+ jmp Main
+.align 2
+
+ResidentMain:
+ /*
+ * Relocate our stack.
+ * Our local stack is big enough for holding the command line and the path
+ * to the executable to start, plus a full DOS_REGISTER_STATE and for one pusha 16-bit.
+ *
+ * FIXME: enlarge it for pushing the needed Load&Exec data.
+ */
+ cli
+ mov ax, ds
+ mov ss, ax
+ mov bp, offset BaseStack
+ lea sp, [bp + (1 + DOS_CMDLINE_LENGTH) + MAX_PATH + 255]
+ sti
+
+ /* Resize ourselves */
+ mov bx, sp // Get size in bytes...
+// sub bx, offset PSP_VAR(PSP)
+ add bx, HEX(0F) // (for rounding to the next paragraph)
+ shr bx, 4 // ... then the number of paragraphs
+ mov ah, HEX(4A)
+ int HEX(21)
+
+ /* Check whether we need to start the 32-bit command interpreter */
+ BOP BOP_CMD, HEX(10) // Check whether we were started from a new console (SessionId != 0)
+ test al, al // and we are not reentering (32-bit process starting a 16-bit process).
+ jz Run
+ cmp word ptr OldParentPsp, SYSTEM_PSP // Check whether our parent is SYSTEM
+ je Run
+
+#ifndef NDEBUG
+/********************************/
+ mov dx, offset Msg1
+ mov ah, HEX(09)
+ int HEX(21)
+/********************************/
+#endif
+
+ BOP BOP_CMD, HEX(0A) // Start 32-bit COMSPEC
+ jnc Quit
+
+ /* Loop for new commands to run */
+Run:
+ /* Initialize the NextCmd structure */
+ mov word ptr FIELD(NextCmd, EnvBlockSeg), ds
+ mov word ptr FIELD(NextCmd, EnvBlockLen), 0 // FIXME
+ mov word ptr FIELD(NextCmd, CmdLineSeg), ds
+ mov word ptr FIELD(NextCmd, CmdLineOff), offset CmdLine
+ mov word ptr FIELD(NextCmd, AppNameSeg), ds
+ mov word ptr FIELD(NextCmd, AppNameOff), offset PgmName
+
+ /* Wait for the next command */
+#ifndef NDEBUG
+/********************************/
+ mov dx, offset Msg2
+ mov ah, HEX(09)
+ int HEX(21)
+/********************************/
+#endif
+
+ // FIXME: Initialize memory with structure for holding CmdLine etc...
+// mov ds, seg NextCmd
+ mov dx, offset NextCmd
+ BOP BOP_CMD, HEX(01)
+ /* Quit if we shell-out */
+ jc Quit
+
+ /* Initialize the DosLoadExec structure */
+// mov word ptr FIELD(DosLoadExec, EnvSeg), 0
+ mov word ptr FIELD(DosLoadExec, CmdLineSeg), ds
+ mov word ptr FIELD(DosLoadExec, Fcb1Seg), ds
+ mov word ptr FIELD(DosLoadExec, Fcb2Seg), ds
+
+ /* Run the command */
+ mov ds, word ptr FIELD(NextCmd, AppNameSeg)
+ mov dx, word ptr FIELD(NextCmd, AppNameOff)
+// mov es, seg DosLoadExec
+ mov bx, offset DosLoadExec
+ pusha // Save the registers in case stuff go wrong
+ // FIXME: Save also SS !!
+ mov ax, HEX(4B00)
+ int HEX(21)
+ popa // Restore the registers
+ // FIXME: Restore also SS !!
+
+ /* Retrieve and set its exit code. Also detect whether
+ * we need to continue or whether we need to quit. */
+ // xor ax, ax
+ // mov ah, HEX(4D)
+ mov ax, HEX(4D00)
+ int HEX(21)
+ /* Send exit code back to NTVDM */
+ mov dx, ax
+ BOP BOP_CMD, HEX(0B)
+
+ /* If we don't shell-out, go and get a new app! */
+ jc Run
+
+ mov al, HEX(00) // ERROR_SUCCESS
+
+Quit:
+ mov bl, al // Save AL in BL
+
+#ifndef NDEBUG
+/********************************/
+ cmp al, HEX(0A)
+ jne XXXX
+ mov dx, offset Msg3
+ mov ah, HEX(09)
+ int HEX(21)
+XXXX:
+/********************************/
+#endif
+
+#ifndef NDEBUG
+ /* Say bye-bye */
+// mov ds, seg QuitMsg
+ mov dx, offset QuitMsg
+ mov ah, HEX(09)
+ int HEX(21)
+#endif
+
+ /* Restore our old parent PSP */
+ mov ax, word ptr OldParentPsp
+ mov PSP_VAR(ParentPsp), ax
+
+ mov al, bl // Restore AL from BL
+
+Exit:
+ /* Return to caller (with possible error code in AL) */
+ mov ah, HEX(4C)
+ int HEX(21)
+ int 3
+
+ /* Does not return */
+
+/* DATA *******************************/
+
+#ifndef NDEBUG
+QuitMsg:
+ .ascii "Bye bye!", CR, LF, "$"
+
+/********************************/
+Msg1: .ascii "Starting COMSPEC...", CR, LF, "$"
+Msg2: .ascii "Waiting for new command...", CR, LF, "$"
+Msg3: .ascii "Bad environment!", CR, LF, "$"
+/********************************/
+#endif
+
+OldParentPsp: .word 0
+CurrentPsp: .word 0
+
+// BOP_CMD, HEX(01) "Get a new app to start" structure
+VAR_STRUCT(NextCmd, NEXT_CMD)
+
+// DOS INT 21h, AH=4Bh "Load and Execute" structure
+VAR_STRUCT(DosLoadExec, DOS_EXEC_PARAM_BLOCK)
+
+// Blank FCB blocks needed for DOS INT 21h, AH=4Bh
+Fcb1:
+ .byte 0
+ .space 11, ' '
+ .space 25, 0
+Fcb2:
+ .byte 0
+ .space 11, ' '
+ .space 25, 0
+
+// The stack resides at the end of the resident code+data
+// and it overwrites the transient part.
+BaseStack:
+
+
+/* TRANSIENT CODE AND DATA ****************************************************/
+
+/* DATA *******************************/
+
+#ifndef NDEBUG
+WelcomeMsg:
+ .ascii "ReactOS DOS32 Command", CR, LF, \
+ "Copyright (C) ReactOS Team 2015" , CR, LF, "$"
+#endif
+
+VerErrMsg:
+ .ascii "Incorrect DOS version", CR, LF, "$"
+
+/* CODE *******************************/
+
+.align 2
+
+Main:
+ /* Setup segment registers */
+ mov ax, cs // cs contains the PSP segment on entry
+ mov ds, ax
+ mov es, ax
+// mov fs, ax
+// mov gs, ax
+ /* Stack is set to cs:FFFE down to cs:09xx by the DOS.
+ * We will need to relocate it before we resize ourselves. */
+
+ /*
+ * Verify DOS version:
+ * - Check whether we are on DOS 5+ (subject to SETVER);
+ * - If so, check our real DOS version and see
+ * whether we are running on NTVDM (version 5.50).
+ */
+ mov ax, HEX(3000)
+ int HEX(21)
+ cmp ax, DOS_VERSION // AH:AL contains minor:major version number
+ jne VerErr
+
+ mov ax, HEX(3306)
+ int HEX(21)
+ cmp bx, NTDOS_VERSION // BH:BL contains minor:major version number
+ je Continue
+
+VerErr:
+ /* Display wrong version error message and exit */
+// mov ds, seg VerErrMsg
+ mov dx, offset VerErrMsg
+ mov ah, HEX(09)
+ int HEX(21)
+ jmp Exit
+
+Continue:
+ /* Save our PSP */
+ mov word ptr CurrentPsp, cs
+/*
+ * The DOS way:
+ *
+ * mov ah, HEX(51) // DOS 2+ internal, or HEX(62) since DOS 3+
+ * int HEX(21)
+ * mov word ptr CurrentPsp, bx
+ */
+
+ /* Save our old parent PSP */
+ mov ax, PSP_VAR(ParentPsp)
+ mov word ptr OldParentPsp, ax
+
+ /* Give us shell privileges: set our PSP as our new parent */
+ mov ax, word ptr CurrentPsp
+ mov PSP_VAR(ParentPsp), ax
+
+#ifndef NDEBUG
+ /* Say hello */
+// mov ds, seg WelcomeMsg
+ mov dx, offset WelcomeMsg
+ mov ah, HEX(09)
+ int HEX(21)
+#endif
+
+ /* Jump to resident code */
+ jmp ResidentMain
+
+.endcode16
+END
+
+/* EOF */
projects / reactos.git / blobdiff