; stdio.h --  Standard interface definitons for the Hawk monitor I/O support.
; language:   SMAL32 assembly language, intended as an include file
; author:     Douglas W. Jones
; date:       Dec 1, 2019

;   Linkage conventions:
;     R1 -- used for return address linkage by all support routines.
;     R2 -- available for use as an activation record pointer.
;     R3 -- typically the first parameter and function return value
;     R4 -- typically the second parameter, if there is one.

;-------------------------------
; linkage to monitor display management routines

	EXT	PUTAT	; set display text coordinates
			;   takes R3=X R4=Y (origin in top left)
			;   wipes out R3-7

	EXT	PUTCHAR	; output one character (same as std C)
			;   takes R3=character
			;   wipes out R4-5, increments X
			; C equivalent: putchar( ch )

	EXT	PUTS	; output one null terminated string (std C, adds LF)
			;   takes R3=string pointer
			;   wipes out R3-7, increments X
			; C equivalent: puts( strptr )

	EXT	PUTSTR	; output one null terminated string (without LF)
			;   takes R3=string pointer
			;   wipes out R3-7, increments X
			; C equivalent: fputs( strptr, stdout )

	EXT	PUTHEX	; output integer in hexadecimal
			;   takes R3=integer to print
			;   takes R4=field width
			;   wipes out R3-7, increments X
			;   uses 1 word of stack
			; C equivalent: fprintf( "%*X", width, integer )

	EXT	PUTDEC	; output signed integer in decimal
	EXT	PUTDECU	; output unsigned integer in decimal
			;   takes R3=integer to print
			;   takes R4=field width
			;   wipes out R3-6, increments X
			;   uses up to 11 words of stack
			; C equivalent: fprintf( "%*d", width, integer )

;-------------------------------
; linkage to monitor keyboard interface

	EXT	GETCHAR	; get a character from the keyboard (std C)
			;   returns R3=character
			;   wipes out R4
			; C equivalent: getchar()

	EXT	GETS	; get null-terminated string from keyboard (std C)
			;   takes R3=pointer to string buffer
			;   wipes out R3-7
			; C equivalent: gets()

;-------------------------------
; terminal info block

	EXT	TERMINFO; global address of info block
TERMROWS=	0	; number of rows on the terminal
TERMCOLS=	4	; number of columns on the terminal

;-------------------------------
; strange accident that NULL is defined here (as in the C standard library)

NULL	=	0