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v4.0-ozzie/bin/DISK2/BIOS/BUGCODE.INC

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+;***	Bugcode.inc - Debug code for including into sysini.asm and ibmbio.asm
+;
+;	Can't link in via buglib due to memory and relocation games played
+;	by these modules.  Each gets a private, local-only copy of these
+;	modules.
+
+
+IFDEF	DEBUGFLG
+
+
+;**	DPRINTF _ Debug Printf
+;
+;	Dprintf is a kernel debug print formatting package.  It is intended
+;	to produce conviently formatted output.
+;
+;	Dprintf is called, indirectly, by a macro:
+;
+;	DEBUG	n,m,"string",<a1,...,an>
+;
+;	string = format string
+;	a1     = first argument
+;	an     = last argument
+;
+;	The format string is an ASCIZ string which can contain 2 types of
+;	specifications:	 data-format specifications and literal characters.
+;	Data format specifications always begin with a '$' character; all
+;	characters not part of a data format specification are treated as
+;	literal characters.
+;
+;	Literal characters
+;	    - any character not part of a format specification.	 Special
+;	      non-printing characters are:
+;		\n	- CRLF
+;		\t	- tab
+;		\b	- bell
+;		\\	- \
+;		\$	- $
+;
+;	Format Specifications
+;
+;	A format specification takes the form:
+;	     $ [@] <char>
+;
+;	where <char> =
+;
+;	    x	    - print argument as a hex word
+;	    d	    - print argument as decimal word
+;	    c	    - print argument as ascii character
+;	    b	    - print argument as hex byte
+;		For each of the above formats, the supplied argument
+;		is a 16-bit word - the value to be printed.  The optional @
+;		(described below) allows a segmented address to be supplied,
+;		instead.
+;
+;	    s[nn]   - print argument as asciz string; if optional decimal
+;		      argument follows the format character this specifys
+;		      a maximum string length.	Non printing characters are
+;		      printed in the form \nnn where "nnn" is the octal byte
+;		      value.
+;		      Note that this format character cannot be directly
+;		      followed by a digit unless that digit is to be taken
+;		      as the start of a length argument.
+;
+;	    Bnn	    - print argument as hex bytes.  The required following
+;		      decimal argument is the number of bytes to print.
+;
+;		Both of these formats take a long address as their argument.
+;		The '@' character is thus invalid for these formats.
+;
+;	WARNINGS
+;	    As befitting a debug routine, DPRINTF does not have a whole lot
+;	    of "failsafe" code in it.  Supplying screwed up formats can
+;	    muck things up.  Specifically:
+;		The @ argument must NOT be specified with the 's' or 'B'
+;		     format
+;		A string/byte-length argument of 0 is taken as 65536
+;	    The string "%% BAD FMT %%" appears in the output when
+;		1) an illegal format specifier is given, or
+;		2) the B format is given a 0 or missing length
+;
+;	ENTRY	(sp+n  ) = address of format string (offset from return cs value)
+;		(sp+n-2) = first argument word
+;		(sp+n-4) = second argument word
+;		    .
+;		(sp+4  ) = last argument word
+;		(sp+2  ) = seg of return address
+;		(sp    ) = offset of return address
+;		(bp) = offset of format string on the stack
+;	EXIT	none
+;	USES	flags
+
+	PUBLIC	DPRINTF
+DPRINTF PROC	near
+
+	push	ds
+	push	es
+	push	bp
+	push	di
+	push	si
+	push	dx
+	push	cx
+	push	bx
+	push	ax		; save registers
+	cld
+
+	mov	si,[bp]		; get address of format string
+	sub	bp,2
+	mov	bx,sp
+	mov	ds,ss:20[bx]	; (ds:si) = address of format string
+	push	cs
+	pop	ds
+
+;	Scan format string for next character
+;
+;	(ds:si) = address of format string
+;	(ss:bp) = address of next argument
+
+dpf1:	lodsb			; (al) = format string byte
+	and	al,al
+	je	dpf3		; all done
+	cmp	al,'$'
+	je	dpf4		; is data escape
+	cmp	al,'\'
+	jnz	dpf2		; got the character
+
+;	it's an "\" escape code - crack the argument character
+
+	lodsb
+	and	al,al
+	je	dpf3		; all done, ignore hanging \
+	xchg	ah,al
+	mov	al,0Ch
+	cmp	ah,'n'
+	jne	dpf1$5		; not \n
+	mov	al,0dH
+	call	putchar
+	mov	al,0aH
+	jmp	SHORT dpf2	; print LF
+
+dpf1$5: cmp	ah,'t'
+	mov	al,9
+	je	dpf2		; is \t
+	cmp	ah,'b'
+	mov	al,7
+	je	dpf2		; is \b
+	xchg	ah,al
+dpf2:	call	putchar
+	jmp	dpf1
+
+;	have the end of the format string - exit
+
+dpf3:	pop	ax
+	pop	bx
+	pop	cx
+	pop	dx
+	pop	si
+	pop	di
+	pop	bp
+	pop	es
+	pop	ds
+	ret
+
+
+;*	Have a '$' character - is data format escape
+;
+;	Get address of data into es:di
+;
+;	(bp) = address of data value
+
+dpf4:	mov	di,bp
+	push	ss
+	pop	es		; (es:di) = address of data value
+	sub	bp,2		; point to next argument
+	lodsb			; (al) = format specifier
+	cmp	al,'@'
+	jne	dpf5		; not an indirect flag
+	les	di,[bp]
+	sub	bp,2		; have an extra 2 for @
+	lodsb
+dpf5:	cmp	al,'x'
+	jne	dpfd1		; not 'x'
+
+;	is 'x' format - print hex word
+
+	mov	ax,es:[di]
+	call	THW		; type hex word
+	jmp	dpf1
+
+dpfd1:	cmp	al,'d'
+	jnz	dpfc1		; not 'd'
+
+;	is 'd' format - print decimal word
+
+	mov	ax,es:[di]
+	call	TDW		; type decimal word
+	jmp	dpf1
+
+dpfc1:	cmp	al,'c'
+	jne	dpfb1
+
+;	is 'c' format - print character
+
+	mov	al,es:[di]
+	call	putchar
+	jmp	dpf1
+
+dpfb1:	cmp	al,'b'
+	jne	dpfs1
+
+;	is 'b' format - print hex byte
+
+	mov	al,es:[di]
+	call	THB		; type hex byte
+	jmp	dpf1
+
+dpfs1:	cmp	al,'s'
+	jne	dpfbb1
+
+;	is 's' format - print ASCIZ string.  First, check for
+;		optional decimal limit
+
+	public	SSB
+SSB:	sub	cx,cx		; set 65536 limit
+	les	di,[bp]		; (es:DI) = fwa of string
+	sub	bp,2		; argument to 's' was two words
+	mov	al,[si]
+	cmp	al,'0'
+	jb	dpfs2		; not decimal
+	cmp	al,'9'
+	ja	dpfs2		; not decimal
+	call	atod		; (ax) = decimal value, (ds:si) updated
+	xchg	cx,ax
+
+;	print asciz string at es:di, max of (cx) characters
+;	(cx) = 0  means max of 65536
+;
+;	Other sections of code in dpf jump here to print strings
+
+dpfs2:	mov	al,es:[di]
+	inc	di
+	and	al,al
+	je	dpfs3
+	call	putchar
+	loop	dpfs2		; continue if not at limit
+dpfs3:	jmp	dpf1
+
+dpfbb1: cmp	al,'B'
+	je	dpfbb2		; is 'B' format
+
+;	error in format code - print message
+
+dpferr: push	cs
+	pop	es
+	mov	di,OFFSET dpfa	; (es:di) = error message
+	sub	cx,cx
+	jmp	dpfs2
+
+dpfa:	DB	'%% BAD FMT %%',0
+
+;	have B format
+
+dpfbb2: call	atod		; (ax) = length specifier
+	jc	dpferr		; number not there - error
+	xchg	cx,ax
+	jcxz	dpferr		; number is 0 - error
+	les	di,[bp]		; (es:DI) = fwa of string
+	sub	bp,2		; argument to 's' was two words
+dpfbb3: mov	al,es:[di]
+	call	THB		; type hex byte
+	mov	al,' '
+	call	putchar		; space em out
+	inc	di
+	loop	dpfbb3		; do em all
+	jmp	dpf1
+
+DPRINTF ENDP
+
+
+;**	THB - Type Hex Byte
+;
+;	THB types a hex byte (via "putchar")
+;
+;	ENTRY	(AL) = byte
+;	EXIT	none
+;	USES	ax, flags
+
+THBA	DB	'0123456789abcdef'
+
+	PUBLIC	THB
+THB	PROC	near
+
+	push	ax
+	shr	al,1
+	shr	al,1
+	shr	al,1
+	shr	al,1
+	and	ax,0fH
+	xchg	bx,ax
+	mov	bl,CS:THBA[bx]
+	xchg	ax,bx
+	call	putchar		    ; put first character
+	pop	ax
+	and	ax,0fH
+	xchg	bx,ax
+	mov	bl,CS:THBA[bx]
+	xchg	ax,bx
+	call	putchar
+	ret
+
+THB	ENDP
+
+
+
+
+;**	THW - Type Hex Word
+;
+;	THW types a word in hex (via "putchar")
+;
+;	ENTRY	(AX) = word
+;	EXIT	none
+;	USES	AX, flags
+
+	PUBLIC	THW
+THW	PROC	near
+
+	push	ax
+	xchg	ah,al
+	call	THB
+	pop	ax
+	call	THB
+	ret
+
+THW	ENDP
+
+
+
+;**	TDW - Type Decimal Word
+;
+;	TDW types (via "putchar") the unsigned decimal representation
+;	of a 16-bit unsigned integer.  Only significant digits are
+;	printed; if the number is 0 a "0" is printed.
+;
+;	ENTRY	(AX) = number
+;	EXIT	none
+;	USES	AX, flags
+
+	PUBLIC	TDW
+TDW	PROC	near
+
+	push	cx		; preserve registers
+	push	dx
+	mov	cx,10
+	call	tdw$		; recurse cracking digits
+	pop	dx
+	pop	cx
+	ret
+
+TDW	ENDP
+
+
+;*	tdw$ - crack number recursively
+;
+;	tdw$ cracks the least significant decimal digit.  If there
+;	are no higher-significant digits, print and return.
+;	else, recurse for higher digits
+;
+;	(AX) = value
+;	(CX) = 10
+
+tdw$	PROC	NEAR
+
+	sub	dx,dx
+	div	cx		; (ax) = quotient, (dx) = remainder
+	and	ax,ax
+	jz	tdw$1		; this is highest-order, do it
+	push	dx
+	call	tdw$
+	pop	dx
+tdw$1:	xchg	ax,dx
+	add	al,'0'
+	call	putchar
+	ret
+
+TDW$	ENDP
+
+
+
+;**	ATOD - Convert ASCII string to decimal number
+;
+;	ATOD is called to convert an ascii string of digits to a
+;	decimal number.	 Digits are converted until we run out of them.
+;
+;	ENTRY	(DS:SI) = address of first digit
+;	EXIT	'C' clear if OK
+;		  (AX) = value
+;		  (SI) updated to first non-digit
+;		'C' set if error - no digits, or result >65535
+;		  (DS:SI) points to error character
+;	USES	AX, SI, FLAGS
+
+	PUBLIC	ATOD
+ATOD	PROC	near
+
+	push	dx
+	push	cx		    ; save registers
+	mov	al,[si]
+	sub	al,'0'
+	jc	atod9		    ; error - no digits
+	cmp	al,10
+	cmc
+	jc	atod9		    ; error - no digits
+	sub	ax,ax		    ; clear accumulator
+	mov	cx,10		    ; base 10
+
+;	crack next digit
+;
+;	(AX) = number accumulated so near
+;	(CX) = 10
+;	(DS:SI) = next character
+
+atod1:	xchg	dx,ax		; keep accum in dx for a while
+	lodsb			; (al) = character
+	sub	al,'0'
+	jc	atod7		; not digit - all done
+	cmp	al,9
+	ja	atod7		; not digit - all done
+	sub	ah,ah		; (ax) = digit value (0 - 9)
+	push	ax
+	xchg	ax,dx
+	mul	cx		; (ax) = 10*accum
+	pop	dx		; (dx) = digit to add
+	jo	atod8		; overflow
+	add	ax,dx
+	jmp	atod1		; go back for more
+
+;	Done with number, all OK
+;
+;	(dx) = number
+;	(ds:si) = address+1 of first unused character
+
+atod7:	clc
+
+;	Done with number, error
+;	'C' set
+
+atod8:	dec	si		; backup over non-decimal (or error) char
+atod9:	pop	cx
+	xchg	ax,dx		; (ax) = number iff no error
+	pop	dx		; restore registers
+	ret			; exit
+
+ATOD	ENDP
+
+;**	putchar - put a character on the console
+;
+;	ENTRY	(al) = character
+;	EXIT	none
+;	USES	ax,flags
+
+
+UR_DAT	=	02f8H		; COM1 = 03f8H, COM2 = 02f8H
+UR_IEN	=	UR_DAT+1	; Interrupt enable
+UR_IER	=	UR_DAT+2	; interrupt ID
+UR_LCR	=	UR_DAT+3	; line control registers
+UR_MCR	=	UR_DAT+4	; modem control register
+UR_LSR	=	UR_DAT+5	; line status register
+UR_MSR	=	UR_DAT+6	; modem status regiser
+UR_DLL	=	UR_DAT		; divisor latch least sig
+UR_DLM	=	UR_DAT+1	; divisor latch most sig
+
+iflag	DB	0		; != 0 when initialized 8250
+
+;*	inchr - input character
+;
+;	EXIT	'z' set if no character
+;		'z' clear if char
+;		  (al) = char
+
+inchr:	mov	dx,UR_LSR
+	in	al,dx
+	and	al,1
+	jz	inchr1
+	mov	dx,UR_DAT
+	in	al,dx
+	and	al,07fh
+inchr1: ret
+
+
+	PUBLIC	putchar
+putchar PROC	NEAR
+	pushf
+	cli
+	push	dx
+	push	cx
+	push	bx
+	push	ax		; (al) = character
+	test	iflag,255
+	jnz	putc1		; is initialized
+	inc	iflag
+
+;	program the usart
+
+	mov	dx,UR_LCR
+	mov	al,80h
+	out	dx,al		; command it
+	sub	al,al
+	mov	dx,UR_DLM
+	out	dx,al
+	mov	dx,UR_DLL
+	mov	al,12		; 9600 baud = 12, 19.2 Kbaud = 6
+	out	dx,al
+	mov	al,3
+	mov	dx,UR_LCR
+	out	dx,al		; command normal mode
+
+;	see if CTL-Q or CTL-S
+
+putc1:	pushf
+	cli
+	call	inchr
+	jz	putc3		; no characters incomming
+	cmp	al,19		; ctl-S?
+	jnz	putc3		; no, ignore
+
+;	have ctl-s.  wait till we see ctl-Q
+
+putc2:	call	inchr
+	jz	putc2
+	cmp	al,17
+	jnz	putc2
+
+putc3:	popf
+	mov	dx,UR_LSR
+putc4:	in	al,dx
+	test	al,020h
+	jz	putc4
+
+;	ready.	crank it out!
+
+	mov	dx,UR_DAT
+
+	pop	ax
+	out	dx,al
+
+	pop	bx
+	pop	cx
+	pop	dx
+	popf
+	ret
+
+putchar ENDP
+
+ENDIF