Initial data commit

Task/String-case/MIPS-Assembly/string-case.mips

@@ -0,0 +1,95 @@
+ToUpper:
+;input: $a0 = pointer to beginning of string
+;clobbers: $t0,$t1,$t2
+
+	li $t1,'a'
+	li $t2,'z'
+ToUpper_again:
+
+	lbu $t0,($a0)
+	nop
+
+	beqz $t0,ToUpper_done     ;if char is null terminator, exit
+	nop
+
+	bltu $t0,$t1,ToUpper_overhead    ;if char stored in $t0 < 'a', skip
+	nop
+
+	bgtu $t0,$t2,ToUpper_overhead    ;if char stored in $t0 > 'z', skip
+	nop
+
+
+	andi $t0,$t0,0xDF        ;otherwise, do the work.
+	sb $t0,($a0)
+
+ToUpper_overhead:
+	addiu $a0,1
+	b ToUpper_again
+	nop
+
+ToUpper_done:
+	jr ra
+	nop
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+ToLower:
+	;input: $a0 = pointer to beginning of string
+	;clobbers: $t0,$t1,$t2
+
+	li $t1,'A'
+	li $t2,'Z'
+ToLower_again:
+
+	lbu $t0,($a0)
+	nop
+
+	beqz $t0,ToUpper_done     		;not a typo, I did this to save space.
+	nop
+
+	bltu $t0,$t1,ToLower_overhead    ;if char stored in $t0 < 'a', skip
+	nop
+
+	bgtu $t0,$t2,ToLower_overhead    ;if char stored in $t0 > 'z', skip
+	nop
+
+
+	ori $t0,$t0,0x20
+	sb $t0,($a0)
+
+ToLower_overhead:
+	addiu $a0,1
+	b ToLower_again
+	nop
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+ToggleCase:
+	li $t1,'A'
+	li $t2,'Z'
+	
+	lbu $t0,($a0)
+	nop
+	
+	beqz $t0,ToggleCase_done
+	nop
+	
+	bltu $t0,$t1,ToggleCase_next
+	nop
+	bleu $t0,$t2,ToggleCase_Xor
+	nop
+ToggleCase_next:
+	addiu $t1,0x20	;li $t1,'a'
+	addiu $t2,0x20	;li $t2,'z'
+	
+	bltu $t0,$t1,ToggleCase_overhead
+	nop
+	bgtu $t0,$t2,ToggleCase_overhead
+	nop
+ToggleCase_Xor:
+	xori $t0,$t0,0x20
+	sb $t0,($a0)
+ToggleCase_overhead:
+	addiu $a0,1
+	b ToggleCase
+	nop
+ToggleCase_done:
+	jr ra
+	nop