Friday March 5th

Write a MAL Program that rads two chars and displays the one that
comes first alphabetically






__start:
	getc $9
	getc $10
	blt $9,$10, firstlower
	put $10
	b end
firstlower:
	putc $9
end:	done


#$8 store first char input
#$9 store last char input
#$10: holds smaller char
#$11: holds newline



Write a MAL program that does the equivalent of 

puts str


.data

str: .asciiz "String"

.text

la $9,str
loop:
lbu $10,($9) 
putc $10
add $9,$9,1
bne $10, $0, loop
done



# Simple int read/write program
# $9: input char
# $10: newline
# $11: '0' (lower limit)
# $12: '9' (upper limit)
# $13: intvalue of the current digit
# $14: intvalue of input

.data
str1: .asciiz "Enter a non-negative integer:"
str2: .asciiz "You've entered: "
str3: .asciiz "Error!"

newline: .byte '\n'
# vars:
int_array .word 0:20

.text

__start:
	puts str1
	lbu $10,newline
	li $11, '0'
	li $12, '9'
	move $14, $0
get_chars:
	getc $9
	beq $9,$10, gotint
	blt $9, $11, interr
	bgt $9, $12, interr
	sub $13, $9, '0'
	mul $14, $14, 10
	add $14, $14, $12
	b get_chars

interr:	puts str3
end:	done


# MAL CODE for wiring out an int.
# $14: int to be printed
# $15: Base Address of the array storing the digits
# $16: Elem Addr of ------^
# $17: Single digit of the int
# $18: Single char digit of the int

get_int:
	puts str2
	la $15, int_array
	move $16, $15
more_digits:
	rem $17, $14, 10
	sw $17, ($16)
	add $16, $16, 4
	div $14, $14, 10
	bgtz $14, more_digits

print_digit:
	sub $16,$16,4
	lw $18,($16)
	add $18,$18,'0'
	putc $18
	bgt $16, $15, print_digit


Tools:
MAL Tester
Run:
%MALtester <Source_File_Name>
If Good:
***********
This is MAL
***********


%simp <Source_File_Name>

easy for remote use
console app
simple simulator

%sim <srcfile>

Simulator
Xterm interface - GUI
Remote Execution requires an xterm emulator

set breakpoints
see contents of registers
Prob: input isnt buffered for sim
simp buffers input so a return mut be entered to finish input



HLL: Procedure call
 x = larger (a,b)

Procedure:

MAL impl of SAL procedure:

Basic steps:

1. Load the return addr
2. Call procedure
3. Execute prcoedure
4. Return

MAL imp of SAL procedure

la $11, rtn1
b proc1

proc1:

jr $11

jal proc1
rtn2: #rtn address is stored in register $31