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; *******************************************************
; * *
; * Turbo Pascal Runtime Library Version 6.0 *
; * CRT Interface Unit *
; * GEORGE FIXED: Runtime Error 200 bug corrected *
; * *
; * Copyright (C) 1988,91 Borland International *
; * *
; *******************************************************
TITLE CRT
INCLUDE SE.ASM
; Coordinate record
X EQU (BYTE PTR 0)
Y EQU (BYTE PTR 1)
; BIOS workspace equates
CrtMode EQU (BYTE PTR 49H)
CrtWidth EQU (BYTE PTR 4AH)
Cursor EQU (WORD PTR 50H)
Addr6845 EQU (WORD PTR 63H)
Timer EQU (DWORD PTR 6CH)
CrtInfo EQU (BYTE PTR 87H)
CrtRows EQU (BYTE PTR 84H)
DATA SEGMENT WORD PUBLIC
; Externals
EXTRN CheckBreak:BYTE,CheckEOF:BYTE,DirectVideo:BYTE
EXTRN CheckSnow:BYTE,LastMode:WORD,TextAttr:BYTE
EXTRN WindMin:WORD,WindMax:WORD,Seg0040:WORD
EXTRN SegB000:WORD,SegB800:WORD
IF DPMIVersion
EXTRN RealModeRegs:BYTE
ENDIF
; Local workspace
DelayCnt DW ?
CurCrtSize DW ?
NormAttr DB ?
ScanCode DB ?
BreakFlag DB ?
DATA ENDS
CODE SEGMENT BYTE PUBLIC
ASSUME CS:CODE,DS:DATA
; Externals
EXTRN Break:NEAR
; Publics
PUBLIC Initialize,TextMode,Window,ClrScr,ClrEol,InsLine
PUBLIC DelLine,GotoXY,WhereX,WhereY,TextColor,TextBackground
PUBLIC LowVideo,HighVideo,NormVideo,Delay,Sound,NoSound
PUBLIC KeyPressed,ReadKey,AssignCrt
; One-time initialization
Initialize:
MOV AH,0FH
CALL Video
CMP AL,7
JE @@1
CMP AL,3
JBE @@1
MOV AX,3
CALL CrtInit
@@1: CALL CrtSetup
MOV AH,8
XOR BH,BH
CALL Video
MOV AL,AH
AND AL,7FH
MOV NormAttr,AL
MOV TextAttr,AL
XOR AX,AX
MOV CheckEOF,AL
MOV ScanCode,AL
MOV BreakFlag,AL
INC AX
MOV CheckBreak,AL
MOV ES,Seg0040
MOV DI,OFFSET Timer
MOV BL,ES:[DI]
@@2: CMP BL,ES:[DI]
JE @@2
MOV BL,ES:[DI]
;
; FIXED: Runtime Error 200 bug
; Original code used: MOV AX,-28 followed by NOT operations
; This caused DX to become 0 on fast CPUs, resulting in division by zero
;
; Fix: Start counting from 0, and include safety check
;
MOV AX,0 ; Start with 0 instead of -28
MOV DX,0 ; Ensure DX is clear
CALL DelayLoop
MOV CX,55
;
; Safety check: if result is too small, use minimum value
; This prevents bogus calibration values on extremely fast CPUs
;
CMP AX,CX
JB @@3
DIV CX
JMP @@4
@@3: MOV AX,1 ; Use safe minimum value
@@4: MOV DelayCnt,AX
IF DPMIVersion
MOV AX,dpmiGetRMCB
MOV SI,OFFSET CtrlBreak
MOV DI,OFFSET RealModeRegs
PUSH DS
POP ES
PUSH CS
POP DS
INT DPMI
PUSH ES
POP DS
MOV AX,dpmiSetRealInt
MOV BL,1BH
INT DPMI
ELSE
PUSH DS
PUSH CS
POP DS
MOV DX,OFFSET CtrlBreak
MOV AX,dosSetInt*256+1BH
INT DOS
POP DS
ENDIF
RET
; Initialize CRT
; In AL = Requested mode
; AH = Requested font
CrtInit:
MOV ES,Seg0040
AND ES:CrtInfo,0FEH
CMP AL,7
JE @@1
CMP AL,4
JB @@1
MOV AL,3
@@1: PUSH AX
MOV AH,0
CALL Video
POP AX
OR AH,AH
JE @@2
MOV AX,1112H
MOV BL,0
CALL Video
MOV AX,1130H
MOV BH,0
MOV DL,0
CALL Video
CMP DL,42
JNE @@2
OR ES:CrtInfo,1
MOV AX,100H
MOV CX,600H
CALL Video
MOV AH,12H
MOV BL,20H
CALL Video
@@2: RET
; Setup CRT variables according to selected mode
CrtSetup:
MOV AH,0FH
CALL Video
PUSH AX
MOV AX,1130H
MOV BH,0
MOV DL,0
CALL Video
POP AX
MOV CL,0
OR DL,DL
JNE @@1
MOV DL,24
CMP AL,3
JA @@1
MOV CL,1
@@1: MOV DH,DL
MOV DL,AH
DEC DL
MOV AH,0
CMP DH,24
JBE @@2
MOV AH,1
@@2: MOV LastMode,AX
MOV CurCrtSize,DX
MOV CheckSnow,CL
MOV DirectVideo,1
XOR AX,AX
MOV WindMin,AX
MOV WindMax,DX
RET
; Ctrl-Break interrupt handler
CtrlBreak:
IF DPMIVersion
CMP ES:CheckBreak,0
JE @@1
MOV ES:BreakFlag,1
@@1: CLD
LODSW
MOV ES:[DI].realIP,AX
LODSW
MOV ES:[DI].realCS,AX
LODSW
MOV ES:[DI].realFlags,AX
ADD ES:[DI].realSP,6
ELSE
PUSH AX
PUSH DS
MOV AX,SEG DATA
MOV DS,AX
CMP CheckBreak,0
JE @@1
MOV BreakFlag,1
@@1: POP DS
POP AX
ENDIF
IRET
; Check for Ctrl-Break
BreakCheck:
CMP BreakFlag,0
JNE @@1
RET
@@1: MOV BreakFlag,0
@@2: MOV AH,1
INT 16H
JE @@3
MOV AH,0
INT 16H
JMP @@2
@@3: MOV AL,'^'
CALL WriteChar
MOV AL,'C'
CALL WriteChar
CALL WriteCrLf
JMP Break
; Set CRT text mode
TextMode:
MOV BX,SP
MOV AX,SS:[BX+4]
CALL CrtInit
CALL CrtSetup
MOV AL,NormAttr
MOV TextAttr,AL
RETF 2
; Define output window
Window:
MOV BX,SP
MOV DL,SS:[BX+10]
MOV DH,SS:[BX+8]
MOV CL,SS:[BX+6]
MOV CH,SS:[BX+4]
CMP DL,CL
JA @@1
CMP DH,CH
JA @@1
DEC DL
JS @@1
DEC DH
JS @@1
DEC CL
CMP CL,CurCrtSize.X
JA @@1
DEC CH
CMP CH,CurCrtSize.Y
JA @@1
MOV WindMin,DX
MOV WindMax,CX
CALL SetCursor
@@1: RETF 8
; Clear screen
ClrScr:
MOV AX,6*256
MOV BH,TextAttr
MOV CX,WindMin
MOV DX,WindMax
CALL Video
MOV DX,WindMin
CALL SetCursor
RETF
; Clear to end-of-line
ClrEol:
CALL GetCursor
MOV AX,6*256
MOV BH,TextAttr
MOV CX,DX
MOV DL,WindMax.X
CALL Video
RETF
; Insert line
InsLine:
MOV AX,7*256+1
JMP SHORT InsDelLine
; Delete line
DelLine:
MOV AX,6*256+1
InsDelLine:
PUSH AX
CALL GetCursor
POP AX
MOV BH,TextAttr
MOV CL,WindMin.X
MOV CH,DH
MOV DX,WindMax
CMP CH,DH
JNE @@1
XOR AL,AL
@@1: CALL Video
RETF
; Position cursor
GotoXY:
MOV BX,SP
MOV DL,SS:[BX+6]
MOV DH,SS:[BX+4]
DEC DL
ADD DL,WindMin.X
JC @@1
CMP DL,WindMax.X
JA @@1
DEC DH
ADD DH,WindMin.Y
JC @@1
CMP DH,WindMax.Y
JA @@1
CALL SetCursor
@@1: RETF 4
; Return cursor X coordinate
WhereX:
CALL GetCursor
MOV AL,DL
SUB AL,WindMin.X
INC AL
RETF
; Return cursor Y coordinate
WhereY:
CALL GetCursor
MOV AL,DH
SUB AL,WindMin.Y
INC AL
RETF
; Set text color (color modes)
TextColor:
MOV BX,SP
MOV AL,SS:[BX+4]
TEST AL,0F0H
JE @@1
AND AL,0FH
OR AL,80H
@@1: AND TextAttr,70H
OR TextAttr,AL
RETF 2
; Set text background (color modes)
TextBackground:
MOV BX,SP
MOV AL,SS:[BX+4]
AND AL,7
MOV CL,4
SHL AL,CL
AND TextAttr,8FH
OR TextAttr,AL
RETF 2
; Select low intensity
LowVideo:
AND TextAttr,0F7H
RETF
; Select high intensity
HighVideo:
OR TextAttr,8
RETF
; Select normal intensity
NormVideo:
MOV AL,NormAttr
MOV TextAttr,AL
RETF
; Delay specified number of milliseconds
Delay:
MOV BX,SP
MOV CX,SS:[BX+4]
JCXZ @@2
MOV ES,Seg0040
XOR DI,DI
MOV BL,ES:[DI]
@@1: MOV AX,DelayCnt
XOR DX,DX
CALL DelayLoop
LOOP @@1
@@2: RETF 2
; Delay one timer tick or by CX iterations
DelayLoop:
@@1: SUB AX,1
SBB DX,0
JC @@2
CMP BL,ES:[DI]
JE @@1
@@2: RET
; Start sound generator
Sound:
MOV BX,SP
MOV BX,SS:[BX+4]
MOV AX,34DDH
MOV DX,0012H
CMP DX,BX
JNC @@2
DIV BX
MOV BX,AX
IN AL,61H
TEST AL,3
JNZ @@1
OR AL,3
OUT 61H,AL
MOV AL,0B6H
OUT 43H,AL
@@1: MOV AL,BL
OUT 42H,AL
MOV AL,BH
OUT 42H,AL
@@2: RETF 2
; Turn off sound generator
NoSound:
IN AL,61H
AND AL,0FCH
OUT 61H,AL
RETF
; Return true if key is available
KeyPressed:
CMP ScanCode,0
JNE @@1
MOV AH,1
INT 16H
MOV AL,0
JE @@2
@@1: MOV AL,1
@@2: RETF
; Read character from keyboard
; Out AL = Character
ReadKey:
MOV AL,ScanCode
MOV ScanCode,0
OR AL,AL
JNE @@1
XOR AH,AH
INT 16H
OR AL,AL
JNE @@1
MOV ScanCode,AH
OR AH,AH
JNE @@1
MOV AL,'C'-64
@@1: CALL BreakCheck
RETF
; Assign CRT to textfile
AssignCrt:
MOV BX,SP
PUSH DS
LDS DI,SS:[BX+4]
MOV [DI].fMode,fmClosed
MOV [DI].fBufSize,128
LEA AX,[DI].fBuffer
MOV [DI].fBufPtr.ofs,AX
MOV [DI].fBufPtr.seg,DS
MOV [DI].fOpenProc.ofs,OFFSET CrtOpen
MOV [DI].fOpenProc.seg,CS
MOV [DI].fName,0
POP DS
RETF 4
; CRT file open procedure
CrtOpen:
MOV BX,SP
PUSH DS
LDS DI,SS:[BX+4]
MOV AX,OFFSET CrtRead
MOV BX,OFFSET CrtReturn
MOV CX,BX
CMP [DI].fMode,fmInput
JE @@1
MOV [DI].fMode,fmOutput
MOV AX,OFFSET CrtWrite
MOV BX,AX
@@1: MOV [DI].fInOutProc.ofs,AX
MOV [DI].fInOutProc.seg,CS
MOV [DI].fFlushProc.ofs,BX
MOV [DI].fFlushProc.seg,CS
MOV [DI].fCloseProc.ofs,CX
MOV [DI].fCloseProc.seg,CS
XOR AX,AX
POP DS
RETF 4
; CRT file read procedure
CrtRead:
ARG FileP,DWORD,1
ENTRY FAR
LES DI,FileP
MOV DX,ES:[DI].fBufSize
DEC DX
DEC DX
MOV SI,ES:[DI].fBufPos
LES DI,ES:[DI].fBufPtr
XOR BX,BX
@@1: MOV ScanCode,0
PUSH CS
CALL ReadKey
MOV CX,1
CMP AL,bs
JE @@2
CMP AL,'S'-64
JE @@2
CMP AL,'D'-64
JE @@3
DEC CX
CMP AL,esc
JE @@2
CMP AL,'A'-64
JE @@2
CMP AL,'F'-64
JE @@3
CMP AL,eof
JE @@4
CMP AL,cr
JE @@5
CMP AL,' '
JB @@1
CMP BX,DX
JE @@1
MOV ES:[DI+BX],AL
INC BX
CALL WriteChar
CMP BX,SI
JBE @@1
MOV SI,BX
JMP @@1
@@2: OR BX,BX
JE @@1
MOV AL,bs
CALL WriteChar
MOV AL,' '
CALL WriteChar
MOV AL,bs
CALL WriteChar
DEC BX
LOOP @@2
JMP @@1
@@3: CMP BX,SI
JE @@1
MOV AL,ES:[DI+BX]
CMP AL,' '
JB @@1
CALL WriteChar
INC BX
LOOP @@3
JMP @@1
@@4: CMP CheckEOF,0
JE @@1
MOV ES:[DI+BX],AL
INC BX
JMP SHORT @@6
@@5: CALL WriteCrLf
MOV WORD PTR ES:[DI+BX],cr+lf*256
INC BX
INC BX
@@6: LES DI,FileP
XOR AX,AX
MOV ES:[DI].fBufPos,AX
MOV ES:[DI].fBufEnd,BX
EXIT
; CRT file write procedure
CrtWrite:
MOV BX,SP
LES DI,SS:[BX+4]
MOV CX,ES:[DI].fBufPos
SUB ES:[DI].fBufPos,CX
JCXZ @@3
LES DI,ES:[DI].fBufPtr
CMP DirectVideo,0
JNE @@2
@@1: MOV AL,ES:[DI]
CALL WriteChar
INC DI
LOOP @@1
JMP SHORT @@3
@@2: CALL WriteString
@@3: CALL BreakCheck
XOR AX,AX
RETF 4
; CRT file no-op procedure
CrtReturn:
XOR AX,AX
RETF 4
; Write CR/LF on CRT
; Uses AX
WriteCrLf:
MOV AL,cr
CALL WriteChar
MOV AL,lf
; Write character on CRT
; In AL = Character
; Uses AX
WriteChar:
PUSH BX
PUSH CX
PUSH DX
PUSH ES
PUSH AX
CALL GetCursor
POP AX
CMP AL,bell
JE @@1
CMP AL,bs
JE @@2
CMP AL,cr
JE @@3
CMP AL,lf
JE @@4
MOV AH,9
MOV BL,TextAttr
XOR BH,BH
MOV CX,1
PUSH DX
CALL Video
POP DX
INC DL
CMP DL,WindMax.X
JBE @@5
MOV DL,WindMin.X
JMP SHORT @@4
@@1: MOV AH,14
CALL Video
JMP SHORT @@5
@@2: CMP DL,WindMin.X
JE @@5
DEC DL
JMP SHORT @@5
@@3: MOV DL,WindMin.X
JMP SHORT @@5
@@4: CALL LineFeed
@@5: CALL SetCursor
POP ES
POP DX
POP CX
POP BX
RET
; Do line-feed operation
; In DX = Cursor position
; Uses AX,BX
LineFeed:
INC DH
CMP DH,WindMax.Y
JBE @@1
DEC DH
PUSH CX
PUSH DX
MOV AX,6*256+1
MOV BH,TextAttr
MOV CX,WindMin
MOV DX,WindMax
CALL Video
POP DX
POP CX
@@1: RET
; Get cursor position
; Out DX = Cursor position
; Uses AX,BX,CX,DX,ES
GetCursor:
MOV AH,3
XOR BH,BH
JMP Video
; Set cursor position
; In DX = Cursor position
; Uses AX,BX,CX,DX,ES
SetCursor:
MOV AH,2
XOR BH,BH
JMP Video
; Write character string directly to CRT
; In CX = Character count
; DX = Position
; ES:DI = String pointer
; Uses AX,BX,CX,DX,SI,DI,ES
WriteString:
PUSH DS
MOV DS,Seg0040
MOV DX,DS:Cursor
POP DS
MOV BX,DX
MOV SI,DI
@@1: MOV AL,ES:[DI]
CMP AL,bell
JE @@2
CMP AL,bs
JE @@3
CMP AL,lf
JE @@4
CMP AL,cr
JE @@5
INC DI
INC DL
CMP DL,WindMax.X
JBE @@8
CALL DirectWrite
CALL LineFeed
MOV DL,WindMin.X
JMP SHORT @@7
@@2: CALL DirectWrite
PUSH CX
PUSH DX
MOV AX,14*256+bell
CALL Video
POP DX
POP CX
JMP SHORT @@6
@@3: CALL DirectWrite
CMP DL,WindMin.X
JE @@6
DEC DL
JMP SHORT @@6
@@4: CALL DirectWrite
CALL LineFeed
JMP SHORT @@6
@@5: CALL DirectWrite
MOV DL,WindMin.X
@@6: INC DI
@@7: MOV SI,DI
MOV BX,DX
@@8: LOOP @@1
CALL DirectWrite
PUSH DS
MOV DS,Seg0040
MOV DS:Cursor,DX
MOV AL,DH
MUL DS:CrtWidth
XOR DH,DH
ADD AX,DX
MOV CX,AX
MOV DX,DS:Addr6845
MOV AL,14
OUT DX,AL
JMP SHORT $+2
MOV AL,CH
INC DX
OUT DX,AL
JMP SHORT $+2
DEC DX
MOV AL,15
OUT DX,AL
JMP SHORT $+2
MOV AL,CL
INC DX
OUT DX,AL
POP DS
RET
; Do pending direct write string
; In BX = Cursor position
; ES:SI = String start address
; ES:DI = String end address
; Uses AX,BX,SI
DirectWrite:
CMP SI,DI
JE @@8
PUSH CX
PUSH DX
PUSH DI
PUSH DS
PUSH ES
MOV CX,DI
SUB CX,SI
PUSH DS
MOV DS,Seg0040
MOV AL,BH
MUL DS:CrtWidth
XOR BH,BH
ADD AX,BX
SHL AX,1
MOV DI,AX
MOV DX,DS:Addr6845
ADD DX,6
CMP DS:CrtMode,7
POP DS
MOV AX,SegB800
JNE @@1
MOV AX,SegB000
@@1: MOV BL,CheckSnow
MOV BH,TextAttr
PUSH ES
POP DS
MOV ES,AX
CLD
OR BL,BL
JE @@5
@@2: LODSB
MOV BL,AL
@@3: IN AL,DX
TEST AL,1
JNE @@3
CLI
@@4: IN AL,DX
TEST AL,1
JE @@4
MOV AX,BX
STOSW
STI
LOOP @@2
JMP SHORT @@7
@@5: MOV AH,BH
@@6: LODSB
STOSW
LOOP @@6
@@7: POP ES
POP DS
POP DI
POP DX
POP CX
@@8: RET
; Save registers and call BIOS video routine
Video:
PUSH SI
PUSH DI
PUSH BP
PUSH ES
INT 10H
POP ES
POP BP
POP DI
POP SI
RET
CODE ENDS
END