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TP&Asm Integrated Compile-Time Assembler Version 2.2 Copyright (c) 1989 Richard W. Prescott All Rights Reserved ═══════ Built-In Assembly Language Support for Turbo Pascal Compilers ═══════ All brand and product names mentioned herein are trademarks or registered trademarks of their respective holders. ┌─────────────────────────────────────────────────────────────────────┐ │ This file contains detailed reference information to enable you to │ │ make effective use of the TP&Asm assembly environment. For general │ │ information on getting started please see the README file. │ └─────────────────────────────────────────────────────────────────────┘ The following topics are described below: 8. Error Messages 9. Trouble Shooting The following additional topics are covered in the separate file TP&ASM.REF: 1. Command Line Options 2. The Assemble Statement 3. The Asm Statement 4. The Internal Statement 5. General Assembler Syntax 6. TP&Asm-specific Options 7. Supported Mnemonics Information specific to the use of TP&Asm with Turbo Pascal 5.5 Objects and Methods can be found in the separate file TP&ASM.OOP. 8. Error Messages The following is an alphabetical listing of all syntax error messages generated by the current version of TP&Asm, together with very brief explanations of messages which are not self-explanitory. All assembler syntax errors use error number 200. [Symbol] Must be declared FORWARD or in INTERFACE INTERNAL Assembly PROCs must be defined in your Pascal Code "Dd $" Not Permitted "Proc/Function + Offset" Not Allowed The Turbo linker does not permit reference to Pascal Procedures and Functions with non-zero numeric offsets. (INTERNAL) Cannot refer to parameters/result by name (INTERNAL) Proc definition expected (WARNING) Altered BP May Prevent Local Variable Access (WARNING) Altered Ds May Prevent Access to Turbo VARs (WARNING) Altered Seg May Prevent Access to Turbo VARs Ss and Bp must be restored before referencing Local variables and parameters by name. Ds must be restored before referencing Global variables and Typed Constants by name. (WARNING) ES may be undefined You have explicitly or implicitly (via a String mnemonic) used the Es register without initializing it. (WARNING) May Require Segment Override TP&Asm will use the default segment for indexed memory references which do not contain a named variable offset. The default segment is Ss for references involving the Bp register, and Ds for all others. (WARNING) Possible invalid operand or forward reference Assembler Symbol Overflow You have attempted to define more than 4K of symbols in the current Assembly block or Internal PROC. Break into smaller blocks or convert some code or data labels to Pascal using LABEL and VAR statements. Bad Identifier Character Bad Identifier Start TP&Asm Code and Data labels may contain only alphanumeric characters and the special characters @, _, $, and ?. They must begin with a letter, @, or _. Base or Index Register Required When Presumptions are disabled you must supply a proper index register (usually [Bp]) to reference local VARs. BY requires Byte operand Byte operand required Cannot Call Short The processor does not support a two byte Call instruction Cannot DUP Address Reference Cannot DUP Forward Reference Cannot EQUate to Assembly Variable Cannot EQUate to Forward Symbol Cannot EQUate to Pascal Symbol Operands to EQU must be numeric expressions or indexed memory references. Cannot Nest Far Procs All Assemble PROCs and nested INTERNAL PROCs must be NEAR. Cannot nest address reference Cannot Nest Memory Reference Cannot Nest Pascal Symbols Parentheses may contain ONLY constants and numeric expressions. Cannot Pop CS Code Label Duplicates Pascal Symbol Since TP&Asm allows forward references to Code labels, Code labels must be unique from all Pascal symbols. Data labels may redefine Pascal symbols (within the current Assemble/Internal statement). Colon or data size specifier required Code labels require ':' or 'PROC'. Data labels require a data definition directive (DB, DW, DD, EQU) or size qualifier (B, W, Byte Ptr, etc). CsData MUST be First Code in Unit A Procedure or Function BEGIN block has preceded the CsData statement. The CsData statement, if used, must be the first code block in the program or unit. Data Name expected Labels are required in Data Segment data allocation statements Duplicate Label Empty quote ENDP Expected EQUate to CODE Symbol not supported Operands to EQU must be numeric expressions or indexed memory references. Error In Define Data Error in IF statement A conditional statement in an (Assembly) Inline directive/MACRO generated no code or exceeded 127 bytes. Error In Jump Statement The operand to a Call or Jmp must be a single Pascal or Assembly label, a single Pascal Procedure or Function identifier, or a variable or memory expression. Error in Mnemonic Invalid symbol found in mnemonic field Full record specification required References to record components must be prefixed by a valid Record Variable or TYPE qualifier, as discussed in the notes to the section on General Assembler Syntax. Incorrect Syntax When the 'Offset' qualifier is used, the DESTINATION operand must be a Register; 'Mov Var1,Offset Var2' is not permitted. INTERNAL Identifier required before NewLine You must specify a unique Pascal identifier on the same line as the keyword 'Internal'. See sample file INTERNAL.PAS. Invalid Absolute CSeg Reference in Assembly MACRO Inline Directives must not make direct reference to code or data labels except in Direct control transfer instructions. Invalid Absolute CSeg Reference Location counter ($) references and data type references to code and data labels are permitted only in the FIRST code block within any program or unit. Location counter ($) references are not permitted in Jumps or EQUates, nor in (Assembly) Inline directive/ MACROS. Note: THIS MESSAGE MAY INDICATE AN UNDEFINED PASCAL SYMBOL. If the undefined symbol is a forward referenced ASSEMBLY symbol, move the code to the FIRST Proc/Function in the Program or Unit. Invalid Address Reference You have specified a sum or difference of symbol names that does not resolve to a valid address, displacement, or pure constant. NOTE: Mov Ax,PasVar1+PasVar2 is not valid because it instructs the assembler to place MemW[Dseg: OFS(PasVar1) +OFS(PasVar2)] into Ax. ( Instead you must: Mov Ax,PasVar1 and then: Add AX,PasVar2 ). Please consult a reference on assembly language programming. Invalid Base Specification [BX] + (implicit) [BP] Disable presumptions to use [BX] in place of the presumed [BP] indexing for local variables. (an Ss override will then be required, as the processor default segment for [Bx] is Ds). Invalid BIT Syntax Example: Or Dx,Bit 6 ; same as Or Dx,64 Invalid Byte/Word Combination Use B or W to override defined variable size: Mov Al,B IntegerVar Mov Ax,Word Ptr ByteVar Invalid Byte/Word/Dword Combination You have attempted to use a DWord POINTER as a Byte or Word VALUE, or the reverse. (Remember that VAR parameters are DWord Pointers). Use B, W, or D to override defined variable size. Invalid Code Reference Within the FIRST code block, expressions of the form "label1-label2+numeric offset" are permitted, where the labels are code or data labels within the current assemble statement. Invalid Conditional Transfer to Proc/Function Pascal Procedure and Function identifiers are not permitted as operands to conditional jumps and loops. Invalid define string operation Arithmetic is not permitted on DB strings with length >= 2. Invalid Final Jump or Forward Reference TP&Asm does not permit the LAST statement in an (Assembly) Inline directive/MACRO to be a zero displacement jump or forward reference. Invalid Forward Absolute CSeg Reference THIS MESSAGE MAY INDICATE AN UNDEFINED PASCAL SYMBOL. If the undefined symbol is a forward referenced Assembly symbol, move the code to the FIRST Proc/Function in the Program or Unit. Invalid Forward Reference in ASM Statement Forward reference to undefined labels is not permitted in an ASM statement. Invalid Forward Symbol Assembly Data labels cannot be forward referenced. Forward Reference to Code labels is permitted only in the FIRST code block in a Program or Unit. Invalid IF Condition Invalid IF Syntax Example: IF A Xor Cx,Cx ; Valid conditions are formed by removing the 'J' from any conditional jump mnemonic EXCEPT jCXZ. Invalid Indirect Option Invalid Indirect Register Indexed memory expressions can combine one base (Bx OR Bp), one index (Si OR Di), and a numeric or symbolic offset. In addition, a segment override and a memory size qualifier may be specified. Examples: Inc B Es:[Bx+Di+SymName+2] ; Shl SymName[Si],1 ; etc. Invalid Jmp Specification Invalid Label or Proc/Function in Memory Reference Pascal Labels and Procedure and Function identifiers are not permitted in memory expressions. Invalid memory operation Arithmetic on memory references is limited to addition and subtraction. Four function arithmetic is supported for constants and numeric expressions only. Invalid Numeric Format Invalid Offset to Pascal Proc/Function Reference The Turbo linker does not permit reference to Pascal Procedures and Functions with non-zero numeric offsets. Invalid operand Invalid operand combination Invalid operand or forward reference Please see USAGE.PAS for examples of valid operands for the given mnemonic and/or consult an assembly language reference. Invalid prefix combination The processor does not support LOCK + repeat prefix Invalid Proc/Function Call in Assembly MACRO Inline Directives cannot make direct calls to Pascal Procedures and Functions. Indirect calls are permitted. Invalid quoted operand Quoted operands used as constants in numeric expressions must have length 1 or 2. Example: Add Al,'A'-1; Quoted WORD operands have most significant CHAR first, thus: Mov Ax,'Ax'; puts 'x' in AL. Note that DB 'ab'; and DW 'ba'; BOTH store the 'a' first since Word data is stored in 'Byte-reverse' format. Invalid Reference in Assembly MACRO Inline Directives must not make direct reference to code or data labels except in Direct control transfer instructions. Invalid Reference to Pascal Label Pascal labels may not be referenced in data manipulation instructions. For example, "Mov Bx,Offset PasLabel" is not permitted. "Mov Bx,Offset AsmLabel" is permitted in the FIRST code block of a Program or Unit. Invalid Relocatable Reference in Assembly MACRO Inline Directives cannot make reference to Pascal Procedure and Function offsets. VAR and (Typed) CONST offsets are permitted. Invalid SEG Syntax Only "SEG DATA" is permitted. Invalid Segment Operation Segment registers are allowed as operands to PUSH, POP, and MOV. Invalid Shift Count The 8086/88 processor supports only 'shift by 1' and 'shift by CL' TP&Asm supports 'shift by n' by coding repeated shifts. The shift count n must be in [1..15]. NOTE: This coding convenience OFTEN generates longer and slower code than a shift using CL. Invalid statement in CsData CsData permits only data allocation statements: Db, Dw, and Dd. Invalid Symbol Possible invalid forward data reference Invalid syntax A colon is not permitted within parentheses. Invalid TP&Asm Directive The combination ;# is reserved for TP&Asm directives. Invalid use of > or < > and < may be used only as prefixes to valid Pascal symbols or (> only) a valid Assembly code label. Invalid Use of String Prefix Only string mnemonics allow repeat prefixes. Invalid use of Type Qualifier Record TYPE qualifiers must be followed by a "." and a valid component for the given TYPE, with no embedded spaces. Invalid use of Unit Qualifier UnitName qualifiers must be followed by a "." and a Global Pascal identifier from the appropriate Unit, with no embedded spaces. Label or Proc/Function Reference Required The operand to a Direct Call or Jmp must be a single Pascal or Assembly label or a single Pascal Procedure or Function identifier. Memory operand required LEA, LDS, and LES require the source operand to be a memory expression. Mismatched Parentheses Multiple Memory Reference The processor does not support memory to memory operations. Note however that Movsb and Cmpsb are effectively memory to memory versions of Mov and Cmp. Multiple Prefix Multiple Segment Override Multiple Segment Prefix Conflicting multiple prefix specifications is an error. (TP&Asm supports Segment+Repeat prefix combinations, however, by coding an appropriate loop). Multiple segments not allowed Assemble allows at most one (optional) Segment statement. Internal allows one (optional) Data Segment and one (required) Code segment. DSeg and CSeg are acceptable synonyms for "Data" and "Code". Nested BY Not Allowed Nested DUP not allowed Nested IFs not allowed Nesting limit exceeded TP&Asm supports 5 levels of parentheses. No Code Assembled An Assemble statement or Internal PROC generated no output code. Non-accessible System Unit identifier Port Array, Mem Array, and Non-standard System Proc/Functions cannot be referenced from assembly language. Object has no Virtual Methods You have attempted to reference ObjectName.VMT for an object which has no virtual method table, or you have incorrectly used "InstanceName.VMT" in place of "ObjectName.VMT". Output Line Code Limit Exceeded A single assembly source line is limited to 28 bytes of output code and/or 5 relocatable references. Long DB strings should be broken or declared in Pascal. Push, Pop, Dw, etc, with repeated operands may (very rarely) need to be coded with fewer repeats on a single line. (Total output for the entire assembly is NOT LIMITED). Parentheses not allowed in memory expressions PAS Statement Invalid in INTERNAL The PAS statement is not permitted within Internal PROCs. Proc Model does not match prior definition You have used PROC NEAR in an Internal statement but the Pascal declaration was FAR (or the reverse). Quotes MisMatch Record/Object Component Expected Reserved Word Error Short Jump Out Of Range Conditional jumps in (Assembly) Inline directive/MACROs are limited to about 127 bytes forward or back. Specify CMPSB or CMPSW Specify LODSB or LODSW Specify MOVSB or MOVSW Specify SCASB or SCASW Specify STOSB or STOSW Specify Word Or Byte Unrecognized Mnemonic Unresolved Reference to [Symbol] A reference was made to a symbol that was never defined in Pascal or Assembly. Forward reference to assembly labels which are not defined in a Pascal LABEL statement must be resolved within the current Assemble statement or Internal PROC. Unsupported ORG Value TP&Asm ignores ORG except to report an error if the specified value is not 0 or $100. Unsupported Radix Value TP&Asm supports Radix 10 and Radix 16. Unsupported Reserved Word 9. Trouble Shooting Examining the TP&Asm Assembly. The utility program EXAMINE.EXE in the archive TP-XMN is provided to facilitate verification that the TP&Asm Assembler has correctly assembled your assembly source code. When used in conjunction with DEBUG.COM (on your DOS disk) it generates a "side by side" display of each Pascal or assembly source statement together with its corresponding DEBUG disassembly. The disassembly you see is the same as you would get if you simply used DEBUG.COM to directly disassemble the compiled EXE file. By displaying each piece of the disassembly alongside the corresponding assembly source statement, it is a simple matter to compare the two to verify proper assembly. Command line options permit you to limit the output to a range containing the assembly code, and to direct the output to the screen, printer, or a file. EXAMINE.EXE requires a compiled EXE file and a MAP file as produced by Turbo/TPC Version 4.0 or above. (Version 4.0 users must also run TPMAP). Please refer to the file EXAMINE.DOC in the archive TP-XMN (or on your distribution disk) for instructions on how to use EXAMINE.EXE. Full source code to EXAMINE.EXE is provided to registered users of TP&Asm. The TP&Asm assembly may also be examined using a symbolic debugger such as the Turbo Debugger. Since TP&Asm is fully integrated with Turbo Pascal, MAP files produced with versions 4.0 and above of the compiler contain full Line Number detail for all assembly sections (Except [Assembly] Inline Directive/MACROs), permitting source level debugging in any MAP-file compatible debugger. Trouble Shooting Using a Debugger. Turbo Pascal Versions 5.0 and above provide an integrated debugger within the Integrated Development Environment. Since Built-in assembly support was not anticipated, however, the integrated debugger provides no means of monitoring the state of the CPU registers and flags. TP&Asm provides support for monitoring and modifying the CPU registers and flags through the Unit(s) WCHMGR5x which are provided on the distribution disk and in the archive TP-ASM. Version 5.x Users: Using WCHMGR5x. With Turbo Version 5.x, you can trace (F7 Trace into, F4 Go to cursor, etc) your assembly code in the turbo integrated debugger. The units WCHMGR5x.TPU define the record variable CPU which permits you to Watch, Evaluate, and Modify the state of all CPU registers and Flags as you Trace. Simply include one of the following statements: Uses WCHMGR50; {- if you are using Turbo Version 5.0 -} Uses WCHMGR55; {- if you are using Turbo Version 5.5 -} at the start of your program. If your program uses other units, these may be specified before or after the Watch Manager Unit. The details of the WCHMGR5x interface section are given below. The following is a series of sample Watch expressions which are particularly useful. (These watch expressions can be set automatically using the procedure AddWatch which is described below. This entire set of watch expressions can be established automatically by calling the procedure SetAsmWatches). CPU.CsIp,p - Segment:Offset of the current instruction CPU.CsIp^,m - Hex Dump beginning at current instruction CPU.Flags-On - Current state of CPU Flags CPU.SsSp,P - Segment:Offset of the Stack Pointer W(CPU.SsSp^),$ - Memory Dump at current Stack Pointer CPU,$R - Lists all register names and contents You can also watch the value of any single register: CPU.Si,$ (etc) - List contents of a Byte or Word Register In these expressions, Pointers, Words, and Bytes are displayed in Hexidecimal. The CPU Flags are displayed as a Pascal Set, eg: [C,P,A,Z,S,I,D] where: C = Carry [Bit 0] P = Parity [Bit 2] A = Auxiliary [Bit 4] Z = Zero [Bit 6] S = Sign [Bit 7] T = Trace [Bit 8] I = Interrupts [Bit 9] D = Direction [Bit 10] O = Overflow [Bit 11] The set "On" is defined to be the set of "Don't Care" bits in the CPU Flags Word. It can be used as in the sample above to supress the display of these "Don't Care" Flags. To Modify a CPU Register: 1) Hit <Ctrl><F4>, type (for example): CPU.AX,$ and press <Enter>. The current value of the Ax register will appear in the Result Box. 2) Move the cursor to the New value Box, type (for example): $1234 and press <Enter>. The value of Ax will change to $1234. 3) Again in the New value Box, type: CPU.BX and press <Enter>. You have accomplished the immediate instruction "Mov Ax,Bx". To Modify the CPU Flags: 1) Hit <Ctrl><F4>, type: CPU.Flags and press <Enter>. The current state of the CPU Flags (including the "Don't Care" bits) will appear in the Result Box. 2) Move the cursor to the New value Box, and type (for example): CPU.Flags - [Z] - to Clear the Zero Flag CPU.Flags + [C] - to Set the Carry Flag Type Definitions from WCHMGR5x.TPU (The variable CPU above is of type CPUType): TYPE FgBits = (C,X1,P,X3,A,X5,Z,S,T,I,D,O,X12,X13,X14,X15); Const On = [X1,X3,X5,X12..X15]; TYPE W = ARRAY[0..32] OF WORD; TYPE CPUType = RECORD Case Integer OF 1: (Ax,Bx,Cx,Dx,Bp,Si,Di,Ds,Es,Ip,Cs,Fg,Sp,Ss :Word); 2: (Al,Ah,Bl,Bh,Cl,Ch,Dl,Dh : Byte); 3: (dum18 :Array[1..18] of byte; CsIp : Pointer; Flags : Set of FgBits; SsSp : Pointer;); END; The units WCHMGR5x.TPU also define four procedures and two functions which may be used to automatically set and clear watch expressions under program control as you trace your program in the Integrated Development Environment. (You are still free to manually set and clear watches in addition to those being set automatically). Using conditional compilation you can easily activate/deactivate the automatic watch control. The interface definitions for the six routines are as follows: PROCEDURE AddWatch(WatchExpr: STRING); PROCEDURE DelWatch(WatchExpr: STRING); PROCEDURE ClrWatch; FUNCTION WatchCount: WORD; FUNCTION WatchStr(WatchNo: WORD): STRING; PROCEDURE SetAsmWatches; AddWatch adds the designated watch expression to the watch window with leading and trailing (but not intermediate) spaces removed. The new watch becomes the "current" (highlighted/bulleted) watch. Like the IDE menu commands, AddWatch permits multiple definitions of the same watch expression. If there is a possibility that a watch may already be defined, call DelWatch before AddWatch to prevent an additional copy from being generated. AddWatch is equivalent to the menu command "Break/Add watch". Example: AddWatch('CPU.CsIp,p'); {Segment:Offset of the current instruction} DelWatch searches for the designated watch expression, and, if found, deletes it from the watch window. Case differences and leading/trailing spaces are ignored in searching for a match. Thus DelWatch(' GLOBALVAR '); will clear the watch set by AddWatch('GlobalVar'); If the deleted watch was the "current" watch, the next older watch becomes "current". Otherwise, the "current" watch is unchanged. If multiple copies of the same watch expression are defined, DelWatch will delete the oldest copy. DelWatch is an extension of the menu command "Break/Delete watch". ClrWatch clears all watch expressions from the watch window. It is equivalent to the menu command "Break/Remove all watches". WatchCount returns the current number of watches defined. There is no IDE equivalent. WatchStr returns the watch expression corresponding to the parameter WatchNo (numbered from oldest to most recent). There is no IDE equivalent. Example: DelWatch(WatchStr(WatchCount)); {delete the most recent watch} SetAsmWatches clears all current watches and then calls AddWatch to establish a set of six useful assembly level watch expressions. Source code for the Unit(s) WchMgr5x is included with the TP&Asm Version 2.2 registration diskette. Version 4.0 Users: Making do with DEBUG. Version 4.0 users can use DEBUG or another external assembler from within the Integrated Environment. The idea is to run Turbo within the debugger and place an "Int 3" instruction in the source code which will be trapped by the debugger when your source program is Run in memory. For this technique it is ESSENTIAL that you run the debugger from TP&Asm (as shown below) rather than the other way around. The following examples illustrate the proper syntax: tpa d turbo <-- to use DEBUG.COM - OR - tpa <debugger> turbo.exe <-- to use an alternate Debugger Note: Some debuggers take certain liberties with the operating system that can interfere with the proper operation of TP&Asm. If you experience difficulty with this technique, try using the standard debugger DEBUG.COM on your DOS system disk. Once inside the Editor environment, insert an INT 3 (Trap to External debugger) into the Assemble/Internal statement under examination, as shown in the example below: PROCEDURE Test(VAR SourceString,DestString: St80; Count: Byte); Assemble Int 3 ;--> Trap to External debugger Mov Cx,Count Lds Si,SourceString Les Di,DestString Rep Movsb <etc> Before continuing: save, Save, SAVE ANY CHANGES! Now Run in Memory. The debugger will Trap and display the Int 3 instruction. At this point you can: - display the disassembly to verify TP&Asm's assembly - OR - - skip past the Int 3 (or patch it from Hex CC to Hex 90 (Nop) ), and then trace your assembly code instruction by instruction. Please refer to the instructions provided with your debugger for information on how to disassemble, trace, and restart your runtime code. If your assembly code has serious errors as discovered in the process of tracing, it may not be possible to restart with a 'g' instruction and return to the editor. In that case you may need to Quit 'q' from the debugger, which will effectively ABORT turbo without saving. Assuming that you heeded the call to Save, Save, Save, above, this presents no problem - and you can now return to the editor environment armed with the knowledge (from the trace) necessary to fix your assembly code (and retest).