BBC Small-C <bbc/os.h> Functions
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		   Release 0.73, xx-xxx-2005, J.G.Harston
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NAME
	os_cli

SYNOPSIS
	void os_cli(s)
	char *s;	/* string to pass to OSCLI */

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NAME
	os_byte

SYNOPSIS
	int os_byte(type, XYparam)
	int type;	/* A register parameter */	
	int XYparam;	/* X and Y register parameter */

DESCRIPTION
	Calls osbyte with A=type, X=XYparam mod 256, Y=XYparam div 256. 
	Returns X+256*Y, ie the value held in XY. 

NOTES
	It is not os_byte(A,X,Y).  It is os_byte(A,X+Y*256) with only two
	parameters. Also, the current implementation does not return the
	carry state.

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NAME
	os_fx

SYNOPSIS
	int os_fx(a, x, y)
	int a;		/* OSBYTE function in A */
	int x;		/* OSBYTE X value */
	int y;		/* OSBYTE Y value */

DESCRIPTION
	Calls osbyte with A,X,Y set to the entry values. Returns the value
	held in X.

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NAME
	os_word

SYNOPSIS
	int os_word(type, address)
	int type;	/* A register parameter */
	int *address;	/* integer parameter block */
		or
	char *address;	/* character parameter block */


DESCRIPTION
	Calls osword with A=type, X=address mod 256, Y=address div 256, ie
	XY points to the parameter block.

NOTES
	Returns Y in the low byte and Carry in the high byte. Note that
	this is only valid with osword 0 - read a line - when it holds the
	returned line length. When working on the second processor, the
	Tube OS only transfers enough of the parameter block that it thinks
	will be suffient.  Bear this in mind when writing and/or using
	extra osword calls.  The lengths are:

		osword 0		Special case - read a line.
		oswords 1 to 20		Varying, enough for the standard
					osword calls and the NFS osword
					primitives.  However, some systems
					don't allow enough for osword 14 -
					read real time clock, reading only
					16 bytes instead of 25.
		oswords 21 to 127	16 bytes.
		oswords 128 to 255	Determined by parameter entries. 
					XY+0 holds the 'send' block length
					and XY+1 holds the 'receive' block
					length.

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NAME
	os_wrch

SYNOPSIS
	os_wrch(c)
	char c;		/* character */

DESCRIPTION
	Sends a character to the oswrch vdu output.  The character is sent
	'pure', no modifications are performed on it as with putc(). 

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NAME
	os_rdch

SYNOPSIS
	int os_rdch(void)

DESCRIPTION
	Returns A in low byte and Carry in second byte.

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NAME
	os_file

SYNOPSIS
	int os_file(type, name, fcb)
	int type;	/* osfile command */
	char *name;	/* filename */
	int *fcb;	/* file control block */

DESCRIPTION
	Calls osfile with A=type and XY=fcb.  Returns the filetype in A.

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long os_args(a, handle, arg);
	int a		OSARGS function in A
	int handle	file handle in Y
	long arg	argument to write, or zero to read

	Returns the new argument.
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int os_bget(handle);
	int handle	file handle in Y

	Returns A in low byte and Carry in second byte.
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int os_bput(ch, handle);
	int ch		character to BPUT in A
	int handle	file handle in Y
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int os_gbpb(a, handle, block);
	int a		OSGBPB function in A
	int handle	file handle in block[0]
	char *block	address of control block in XY

	Returns A in low byte and Carry in second byte.
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int os_find(a, name);
	int a		OSFIND function in A
	char *name	filename

	Returns file handle in A
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void os_close(handle);
	int handle	OSFIND handle in Y
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char *os_report();

	Returns address of error block from &FD/&FE.
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void os_error(err, s);
	int err		error number
	char *s		error string

	Generates a BRK error.
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int os_escape();

	Returns the escape state from &FF
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void os_onerror(f);
	void *f(void)	function to jump to when an error occurs, or NULL
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char *os_call(regs);
	char *regs	register block A,X,Y,P,PC

	Returns pointer to a register block holding A,X,Y,P
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int os_host()
	Returns the current BBC host type, as follows:

Note: provisional, will be changed
#define _kernel_HOST_UNDEFINED    -1
#define _kernel_BBC_MOS1_0         0
#define _kernel_BBC_MOS1_2         1
#define _kernel_BBC_ACW            2
#define _kernel_BBC_MASTER         3
#define _kernel_BBC_MASTER_ET      4
#define _kernel_BBC_MASTER_COMPACT 5
#define _kernel_ARTHUR             6
#define _kernel_RISC_OS            6
#define _kernel_SPRINGBOARD        7
#define _kernel_A_UNIX             8
#define _kernel_AMSTRAD           30
#define _kernel_SPECTRUM          31
#define _kernel_PC                32
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#define __bbc__
	Macro defined when targetting the BBC platform
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