; FILENAME: IMACROS.MAC ; ; Copyright (c) 1988, 1989 by Borland International, Inc. ; ; DESCRIPTION: This include file implements miscellaneous useful macros. ; The file uses ideal mode syntax. ; ; ASSEMBLY INSTRUCTIONS: If assembling modules for 286/386 processors, ; turn on the P286 directive in order to take advantage of 286/386 specific ; instructions. I.E. ; ; TASM filename /jP286 ; ; NOTE: In order to use this macro file you must also include the macro file ; IBIOS.MAC in your module. ; ; The macros implemented in this file are: ; Name Function ; --------------- --------------------------------------------------- ; FarPtrAddress Calculate the absolute address of a 32-bit pointer ; CompareFarPointers Compare two 32-bit pointers ; MakePascalString Allocate a string using Turbo Pascal format ; InitStack Initialize the stack registers for parameter access ; RestoreStack Restore the stack registers ; GetVideoAddress Determine the segment address of video ram ; DosCall Performs the DOS int 21h call ; LoadSegment Loads a segment register with a value ; Beep Sounds the speaker ; The following macro calculates the absolute address of the far pointer ; passed to it. ; ; Input ; Segment:Ofs - Far pointer ; Output ; dx:ax - Absolute address of pointer(20 bits) ; Calling convention ; NA ; Registers modified ; ax, bx, cx, dx, Flags macro FarPtrAddress Segment, Ofs ifb display "Segment parameter must be provided in call to FarPtrAddress" err endif ifb display "Ofs parameter must be provided in call to FarPtrAddress" err endif mov bx, Segment ; Calculate the low 12 bits and bx, 0FFFh if (@Cpu and 100b) eq 100b ; Shift the segment value right 12 bits shl bx, 4 ; to prepare for addition else mov cl, 4 shl bx, cl endif mov dx, Segment if (@Cpu and 100b) eq 100b ; Shift the segment value right 12 bits shr dx, 12 ; to prepare for addition else mov cl, 12 shr dx, cl endif mov ax, Ofs ; Determine the low 16 bits of the 20-bit add ax, bx ; address adc dx, 0 ; Calculate the absolute segment endm ; The following macros compares two far pointers to determine their ; relative absolute addresses. ; ; Input ; Seg1:Ofs1 - Far pointer ; Seg2:Ofs2 - Far pointer ; Output ; The Flags register is set by the CMP instruction. ; Calling convention ; NA ; Registers modified ; ax, bx, cx, dx, Flags macro CompareFarPointers Seg1, Ofs1, Seg2, Ofs2 local Exit, SegmentsEqual ifb display "Need to declare Seg1 in call to CompareFarPointers" err endif ifb display "Need to declare Seg2 in call to CompareFarPointers" err endif ifb display "Need to declare Ofs1 in call to CompareFarPointers" err endif ifb display "Need to declare Ofs2 in call to CompareFarPointers" err endif mov ax, Seg1 ; Load segment registers mov dx, Seg2 cmp ax, dx ; Check if segment registers are equal je short SegmentsEqual ; If the segments aren't equal we have to calculate the absolute ; addresses of the pointers FarPtrAddress Seg1, Ofs1 ; Calculate absolute adress of Seg1:Ofs1 push dx ; Store calculated values on the stack push ax FarPtrAddress Seg2, Ofs2 ; Calculate absolute adress of Seg2:Ofs2 mov bx, sp cmp [ss:bx+2], dx ; Compare absolute segment adresses pop bx ; Clean up the stack pop bx jne short Exit ; If they aren't equal we're done cmp [ss:bx], ax ; Check absolute offsets jmp short Exit SegmentsEqual: cmp Ofs1, Ofs2 ; Compare offsets Exit: endm ; The following macro builds strings using Turbo Pascal conventions. That ; is, the string is stored with a preceding 'length byte.' This macro is ; an excellent example of the clever things that can be done using the ; ORG directive. ; ; Input ; Id - Label to associate with the string ; Msg - Contents of the string ; Output ; none ; Calling convention ; NA ; Registers modified ; none macro MakePascalString Id, Msg local MsgLen, EndStr ifb display "Must pass name of string to MakePascalString" err else ifb display "Must pass string parameter to MakePascalString err else Id db EndStr - Id - 1, &Msg& ; Allocate space for the string label EndStr byte ; a preceding byte storing the endif ; length of the string. endif endm ; The following macro initializes bp and sp in preparation for access ; of parameters passed to a routine on the stack. The parameter LocalVars ; is optional and if provided indicates the amount of space that should ; be reserved for local variables. LocalVars must be an even value. ; ; Input ; LocalVars - # of bytes to reserve for local variables ; Output ; none ; Calling convention ; NA ; Registers modified ; bp, sp macro InitStack LocalVars push bp ; Set up the stack for a sub-routine mov bp, sp ifnb sub sp, LocalVars ; Make space for local variables endif endm ; The following macro restores bp and sp after a routine is finished ; accessing parameters passed to a routine on the stack. The parameter ; LocalVars is optional and if provided indicates the amount of space ; that was reserved for local variables. LocalVars must be an even value. ; ; Input ; LocalVars - # of bytes that were reserved for local variables ; Output ; none ; Calling convention ; NA ; Registers modified ; bp, sp macro RestoreStack LocalVars ifnb add sp, LocalVars endif ; ifnb pop bp endm ; InitStack ; The following macro returns the current segment address of video ram. ; ; Input ; none ; Output ; ax ; Calling convention ; NA ; Registers modified ; ax, bx, Flags macro GetVideoAddress local Color, Exit GetVideoMode cmp al, 07h jne short Color mov ax, 0B000h ;; It's a monochrome card jmp short Exit Color: mov ax, 0B800h ;; It's a color card Exit: endm ; The following macro performs the Int 21h call to execute DOS's ; services. ; ; Input ; Service - Service # to execute ; Output ; None ; Calling convention ; NA ; Registers modified ; NA macro DosCall Service ifb display "The Service parameter must be provided to DosCall err endif mov ah, Service int DOS_FUNCTION endm ; The following macro loads a segment register with a value. The macro ; attempts to do all possible checks to determine the type of the value ; being moved into the segment register. Based on this information it ; generates the correct code. ; ; Input ; Segm - Segm register to load value into ; Value - Value to put on the stack ; Output ; none ; Calling convention ; NA ; Registers modified ; ax macro LoadSegment Segm, Value local IsSegReg macro CheckRegisterName Register IsSegReg = 0 if (symtype Register) eq 110000b irp Reg, ifidni , <&Reg&> IsSegReg = 1 ; Return that the register exitm ; is a segment register endif endm endif endm CheckRegisterName ; Check if the value to be if IsSegReg ; loaded into the segment push Value ; register is itself a pop Segm ; segment register. else if (symtype Segm eq 24h) or (symtype Segm eq 0h) ; Parameter is a constant mov ax, Value mov Segm, ax else mov Segm, Value ; Value is a memory reference endif endif endm ; The following macro generates a beep by displaying the ASCII Bell ; character. ; ; Input ; none ; Output ; none ; Calling convention ; NA ; Registers modified ; ax, dl macro Beep mov dl, BELL DosCall DOS_CHARACTER_OUTPUT endm