;=======================================================
;=== C_UTILS.ASM - Asm Utilities for C/C++ ===
;=======================================================
PAGE 255, 132
.MODEL Medium
.286
; ==== MACROS ====
; macros to PUSH and POP multiple registers
PUSHx MACRO R1, R2, R3, R4, R5, R6, R7, R8
IFNB <R1>
push R1 ; Save R1
PUSHx R2, R3, R4, R5, R6, R7, R8
ENDIF
ENDM
POPx MACRO R1, R2, R3, R4, R5, R6, R7, R8
IFNB <R1>
pop R1 ; Restore R1
POPx R2, R3, R4, R5, R6, R7, R8
ENDIF
ENDM
; Macro to Clear a Register to 0
CLR MACRO Register
xor Register, Register ; Set Register = 0
ENDM
; Macros to Decrement Counter & Jump on Condition
LOOPx MACRO Register, Destination
dec Register ; Counter--
jnz Destination ; Jump if not 0
ENDM
LOOPjz MACRO Register, Destination
dec Register ; Counter--
jz Destination ; Jump if 0
ENDM
; ==== General Constants ====
False EQU 0
True EQU -1
nil EQU 0
b EQU BYTE PTR
w EQU WORD PTR
d EQU DWORD PTR
o EQU OFFSET
f EQU FAR PTR
s EQU SHORT
?x4 EQU <?,?,?,?>
?x3 EQU <?,?,?>
.Data
EVEN
RND_Seed DW 7397, 29447, 802
RND_Mult DW 179, 183, 182
RND_ModV DW 32771, 32779, 32783
CR_LF DB 13, 10 ; the CRLF data
.Code
;===========================================
;void far pascal dos_print (far char *Text)
;===========================================
;
; - Print Text Directly to DOS console w/ CR/LF
;
PUBLIC DOS_PRINT
DP_Stack STRUC
DW ?x4 ; DI, SI, DS, BP
DD ? ; Caller
DP_Text DD ? ; Far Address of Text to print
DP_Stack ENDS
DOS_PRINT PROC FAR
PUSHx BP, DS, SI, DI ; Preserve Important Registers
mov BP, SP ; Set up Stack Frame
lds DX, [BP].DP_Text ; Get Addr of Text$ descriptor
; Compute Length of string
CLR CX ; Length = 0
mov SI, DX ; DS:SI = String data
@@DP_Scan_it:
cmp b [SI], 0 ; Null Byte found?
je @@DP_Got_Len ; exit loop if so
inc CX ; Len++
inc SI ; Point to next char
jmp s @@DP_Scan_it ; check again...
@@DP_Got_len:
jcxz @No_Print ; Don't Print if empty
mov BX, 1 ; 1= DOS Handle for Display
mov AH, 40h ; Write Text Function
int 21h ; Call DOS to do it
@No_Print:
mov AX, SEG DGROUP ; Restore DGroup
mov DS, AX
mov DX, o CR_LF ; Get Addr of CR/LF pair
mov CX, 2 ; 2 Characters to Write
mov BX, 1 ; 1= DOS Handle for Display
mov AH, 40h ; Write Text Function
int 21h ; Call DOS to do it
cld ; Reset Direction Flag
POPx DI, SI, DS, BP ; Restore Saved Registers
ret 4 ; Exit & Clean Up Stack
DOS_PRINT ENDP
;===========================================
;void far pascal dos_prints (char far *Text)
;===========================================
;
; Print Text Directly to DOS console
; without a trailing CR/LF
;
PUBLIC DOS_PRINTS
DOS_PRINTS PROC FAR
PUSHx BP, DS, SI, DI ; Preserve Important Registers
mov BP, SP ; Set up Stack Frame
lds DX, [BP].DP_Text ; Get Addr of Text$ descriptor
; Compute Length of string
CLR CX ; Length = 0
mov SI, DX ; DS:SI = String data
@@DPS_Scan_it:
cmp b [SI], 0 ; Null Byte found?
je @@DPS_Got_Len ; exit loop if so
inc CX ; Len++
inc SI ; Point to next char
jmp s @@DPS_Scan_it ; check again...
@@DPS_Got_len:
jcxz @DPS_Exit ; Don't Print if empty
mov BX, 1 ; 1= DOS Handle for Display
mov AH, 40h ; Write Text Function
int 21h ; Call DOS to do it
@DPS_Exit:
cld ; Reset Direction Flag
POPx DI, SI, DS, BP ; Restore Saved Registers
ret 2 ; Exit & Clean Up Stack
DOS_PRINTS ENDP
;=========================================
;void far pascal set_video_mode (int Mode)
;=========================================
;
; Sets the Video Mode through the BIOS
;
PUBLIC SET_VIDEO_MODE
SVM_Stack STRUC
DW ?x4 ; DI, SI, DS, BP
DD ? ; Caller
SVM_Mode DB ?,? ; Desired Video Mode
SVM_Stack ENDS
SET_VIDEO_MODE PROC FAR
PUSHx BP, DS, SI, DI ; Preserve Important Registers
mov BP, SP ; Set up Stack Frame
CLR AH ; Function 0
mov AL, [BP].SVM_Mode ; Get Mode #
int 10H ; Change Video Modes
@SVM_Exit:
POPx DI, SI, DS, BP ; Restore Saved Registers
ret 2 ; Exit & Clean Up Stack
SET_VIDEO_MODE ENDP
;===================================
;int far pascal scan_keyboard (void)
;===================================
;
; Function to scan keyboard for a pressed key
;
PUBLIC SCAN_KEYBOARD
SCAN_KEYBOARD PROC FAR
PUSHx BP, DS, SI, DI ; Preserve Important Registers
mov AH, 01H ; Function #1
INT 16H ; Call Keyboard Driver
JZ @SK_NO_KEY ; Exit if Zero flag set
mov AH, 00H ; Remove Key from Buffer
INT 16H ; Get Keycode in AX
OR AL, AL ; Low Byte Set (Ascii?)
JZ @SK_Exit ; if not, it's a F-Key
CLR AH ; Clear ScanCode if Ascii
JMP s @SK_Exit ; Return Key in AX
@SK_NO_KEY:
CLR AX ; Return Nil (no Keypress)
@SK_Exit:
cld ; Reset Direction Flag
POPx DI, SI, DS, BP ; Restore Saved Registers
ret ; Exit & Clean Up Stack
SCAN_KEYBOARD ENDP
;========================================
;int far pascal random_int (int MaxValue)
;========================================
;
; Returns a pseudo-random number in the range of (0.. MaxInt-1)
;
PUBLIC RANDOM_INT
RI_Stack STRUC
DW ? ; BP
DD ? ; Caller
RI_MaxVal DW ? ; Maximum Value to Return + 1
RI_Stack ENDS
RANDOM_INT PROC FAR
push BP ; Preserve Important Registers
mov BP, SP ; Set up Stack Frame
CLR BX ; BX is the data index
CLR CX ; CX is the accumulator
REPT 3
mov AX, RND_Seed[BX] ; load the initial seed
mul RND_Mult[BX] ; multiply it
div RND_ModV[BX] ; and obtain the Mod value
mov RND_Seed[BX], DX ; save that for the next time
add CX, DX ; add it into the accumulator
inc BX
inc BX ; point to the next set of values
ENDM
mov AX, CX ; AX = Random #
CLR DX ; DX = 0
div [BP].RI_MaxVal ; DX = DX:AX / MAxVal Remainder
mov AX, DX
pop BP ; Restore BP
ret 2 ; back to BASIC with AX holding the result
RANDOM_INT ENDP
;==================================
;void far pascal init_random (void)
;==================================
;
; Scrambles the psuedo-random number sequence
; (XOR's the seed value with the timer)
;
PUBLIC INIT_RANDOM
INIT_RANDOM PROC FAR
CLR AX ; Segment = 0000
mov ES, AX
mov AX, ES:[046Ch] ; Get Timer Lo Word
xor RND_Seed, AX ; Scramble 1st Seed
ret ; Exit & Clean Up Stack
INIT_RANDOM ENDP
;=========================================
;int far pascal int_sqr (int X, int Round)
;=========================================
;
; Returns the Integer Square Root of (X)
; Round allows the return value to be rounded to the
; nearest integer value by passing 0x80. Passing 0
; return the Integer Portion only. The rounding amound is
; a number from 0 to 1 multiplied by 256, thus
; 0.5 * 0x100 = 0x80!
;
ISQ_Stack STRUC
DW ?,? ; BP, DI
DD ? ; Caller
ISQ_Round DW ? ; Amount to Round Result * 256
ISQ_X DW ? ; "X"
ISQ_Stack ENDS
PUBLIC INT_SQR
INT_SQR PROC FAR
PUSHx BP, DI ; Save BP
mov BP, SP ; Set up Stack Frame
xor AX, AX ; {xor eax,eax}
xor DX, DX ; {xor edx,edx}
mov DI, [BP].ISQ_X ; {mov edi,x}
mov CX, 16 ; {mov cx, 32}
@ISQ_L:
shl DI, 1 ; {shl edi,1}
rcl DX, 1 ; {rcl edx,1}
shl DI, 1 ; {shl edi,1}
rcl DX, 1 ; {rcl edx,1}
shl AX, 1 ; {shl eax,1}
mov BX, AX ; {mov ebx,eax}
shl BX, 1 ; {shl ebx,1}
inc BX ; {inc ebx}
cmp DX, BX ; {cmp edx,ebx}
jl @ISQ_S
sub DX, BX ; {sub edx,ebx}
inc AX ; {inc eax}
@ISQ_S:
loop @ISQ_L
add ax, [BP].ISQ_Round ; {add eax,$00008000}
; {*round* result in hi word: ie. +0.5}
shr ax, 8 ; {shr eax,16} {to ax (result)}
POPx DI, BP ; Restore Registers
ret 4 ; Exit
INT_SQR ENDP
;=================================
;int far pascal timer_count (void)
;=================================
;
; Returns the current timer value as an integer/long integer
;
PUBLIC TIMER_COUNT
TIMER_COUNT PROC FAR
CLR AX ; Segment = 0000
mov ES, AX
mov AX, ES:[046Ch] ; Get Timer Lo Word
mov DX, ES:[046Eh] ; Get Timer Hi Word
ret ; Exit & Clean Up Stack
TIMER_COUNT ENDP
END
