;       bitswap: PeANUt assembler (test) program for COMP2300 Lab Exercise 5

macro Put (e)           ; write value of e to terminal
        load    e               ; (AC = <value referred by e>)
        trap    #3              ; (AC(0:7) written to standard output)
endmacro

macro Call2 (Proc, e1, e2); call procedure Proc, with 2 value parameters (e1,e2)
                        ;  or a function Proc, with 1 value parameter (e2)
                        ;     and stack is used for return value (e1=#0)
        load    e1              ; (AC = <value referred by e1>)
        incsp   #1              ; (SP = SP + 1)
        store   !0              ; (Memory[SP] = AC)
        load    e2              ; (AC = <value referred by e2>)
        incsp   #1              ; (SP = SP + 1)
        store   !0              ; (Memory[SP] = AC)
        call    Proc            ; (call procedure Proc)
        incsp   #-2             ; (restore stack)
endmacro

; This program inputs a character, prints it out in character and
; binary form, and prints out the character with bits 0..3 and bits 4..7
; swapped.
                                ; #include <stdio.h>
external WriteBin		; #include "fpio.h"
external SwapBits		; #include "swapbits.h" /*SwapBits()*/
                                ; int main() {
ch:	block	1		;   char ch: CHAR; 	 	
ch1:	block	1		;   unsigned short int ch1;     /* copy of ch */
bitswap:			; 
	trap	#2		;   ch = getchar();
	store	ch		;
	load	ch		;   ch1 = ch;
	store	ch1		;
				;   SwapBits( &ch );	/* pass address of ch */
				;
				;
				;
				;
	Put	(ch1)		;   putchar(ch1);
	Put	(#' ')		;   putchar(' ');
	Call2	(WriteBin, ch1, #8);WriteBin( ch1, 8 );
	Put	(#'\n')		;   putchar('\n');
				;
	Put	(ch)		;   putchar(ch);
	Put	(#' ')		;   putchar(' ');
	Call2	(WriteBin, ch, #8); WriteBin( ch, 8 );
	Put	(#'\n')		;   putchar('\n');
	trap	#1		; } /*main() */
	end	bitswap		;