2016 Update

Task/Determine-if-a-string-is-numeric/MIPS-Assembly/determine-if-a-string-is-numeric.mips

@@ -0,0 +1,51 @@
+# $a0 char val
+# $a1 address pointer
+# $a2 PERIOD_HIT_FLAG
+# $a3 HAS_DIGITS_FLAG
+
+.data
+			### CHANGE THIS STRING TO TEST DIFFERENT ONES... ###
+	string: .asciiz "-.1236"
+	s_false: .asciiz "False"
+	s_true: .asciiz "True"
+.text
+main:
+	set_up: #test for 0th char == 45 or 46 or 48...57
+		la $a1,string
+		lb $a0,($a1)
+		beq $a0,45,loop # == '-'
+		beq $a0,46,loop # == '.'
+		blt $a0,48,exit_false # isn't below the ascii range for chars '0'...'9'
+		bgt $a0,57,exit_false # isn't above the ascii range for chars '0'...'9'
+	loop:
+		addi $a1,$a1,1
+		lb $a0,($a1)
+		beqz $a0,exit_true # test for \0 null char
+		beq $a0,46,period_test #test for a duplicate period
+		blt $a0,48,exit_false  #test for
+		bgt $a0,57,exit_false
+		la $a3,1 #set the HAS_DIGITS flag. This line is only reached because the
+			 #    tests for period and - both jump back to start.
+		j loop
+	
+exit_true:
+	beqz $a3,exit_false
+	la $a0,s_true
+	la $v0,4
+	syscall
+
+	li $v0,10
+	syscall	
+
+exit_false:
+	la $a0,s_false
+	la $v0,4
+	syscall
+	
+	li $v0,10
+	syscall
+	
+period_test:
+	beq $a2,1,exit_false
+	li $a2,1
+	j loop