diff --git a/2ano/2semestre/ac2/aula01/addicional-1.c b/2ano/2semestre/ac2/aula01/addicional-1.c
new file mode 100644
index 0000000..3505d61
--- /dev/null
+++ b/2ano/2semestre/ac2/aula01/addicional-1.c
@@ -0,0 +1,39 @@
+#include <detpic32.h>
+
+#define UP 1
+#define DOWN 0
+
+void wait(int);
+
+int main(void) {
+    int state = 0;
+    int cnt = 0;
+    char c;
+    do {
+        putChar('\r'); // Carriage return character
+        printInt(cnt, 10 | 3 << 16); // 0x0003000A: decimal w/ 3 digits
+        putChar('\t'); // Tab character
+        printInt(cnt, 2 | 8 << 16); // 0x00080002: binary w/ 8 bits
+
+        wait(5); // wait 0.5s
+
+        c = inkey();
+        if (c == '+')
+            state = UP;
+        if (c == '-')
+            state = DOWN;
+        if (c == 'S')
+            while (inkey() != 'R');
+
+        if (state == UP)
+            cnt = (cnt + 1) & 0xFF; // Up counter MOD 256
+        else
+            cnt = (cnt - 1) & 0xFF; // Down counter MOD 256
+    } while (c != 'q');
+    return 0;
+}
+
+void wait(int ts) {
+    int i;
+    for (i = 0; i < 515000 * ts; i++); // wait approximately ts/10 seconds
+}
diff --git a/2ano/2semestre/ac2/aula01/addicional-1.s b/2ano/2semestre/ac2/aula01/addicional-1.s
new file mode 100644
index 0000000..161085a
--- /dev/null
+++ b/2ano/2semestre/ac2/aula01/addicional-1.s
@@ -0,0 +1,107 @@
+	.equ	INKEY, 1
+	.equ	GETCHAR, 2
+	.equ	PUTCHAR, 3
+	.equ	READ_INT, 4
+	.equ	READ_INT10, 5
+	.equ	PRINT_INT, 6
+	.equ	PRINT_INT10, 7
+	.equ	PRINT_STR, 8
+	.equ	READ_STR, 9
+	.equ	EXIT, 10
+	.equ	READ_CORE_TIMER, 11
+	.equ	RESET_CORE_TIMER, 12
+
+	.equ	UP, 1
+	.equ	DOWN, 0
+
+	.data
+	.text
+	.globl main
+
+# Mapa de registos
+# $t0	→ state
+# $t1	→ cnt
+# $t2	→ c
+
+main:
+	li	$t0, 0
+	li	$t1, 0
+
+do:
+	li	$a0, '\r'
+	li	$v0, PUTCHAR
+	syscall
+
+	move	$a0, $t1
+	li	$a1, 3
+	sll	$a1, $a1, 16
+	ori	$a1, $a1, 10
+	li	$v0, PRINT_INT
+	syscall
+
+	li	$a0, '\t'
+	li	$v0, PUTCHAR
+	syscall
+
+	move	$a0, $t1
+	li	$a1, 8
+	sll	$a1, $a1, 16
+	ori	$a1, $a1, 2
+	li	$v0, PRINT_INT
+	syscall
+
+	addi	$sp, $sp, -16
+	sw	$ra, 0($sp)
+	sw	$t0, 4($sp)
+	sw	$t1, 8($sp)
+	sw	$t2, 12($sp)
+	li	$a0, 5
+	jal	wait
+	lw	$ra, 0($sp)
+	lw	$t0, 4($sp)
+	lw	$t1, 8($sp)
+	lw	$t2, 12($sp)
+	addi	$sp, $sp, 16
+	
+	li	$v0, INKEY
+	syscall
+	move	$t2, $v0
+
+	beq	$t2, '+', if_plus
+	beq	$t2, '-', if_minus
+	beq	$t2, 'S', if_stop
+	j	if
+if_plus:
+	li	$t0, UP
+	j	if
+if_minus:
+	li	$t0, DOWN
+	j	if
+if_stop:
+	li	$v0, INKEY
+	syscall
+	move	$t2, $v0
+	bne	$t2, 'R', if_stop
+
+if:
+	bne	$t0, UP, else
+	addi	$t1, $t1, 1
+	andi	$t1, $t1, 0xFF
+	j	endif
+else:
+	addi	$t1, $t1, -1
+	andi	$t1, $t1, 0xFF
+endif:
+	bne	$t2, 'q', do
+	jr	$ra
+
+
+wait:
+	li	$t0, 0
+	mul	$t1, $a0, 515000
+wait_loop:
+	bge	$t0, $t1, wait_return
+	addi	$t0, $t0, 1
+	j	wait_loop
+wait_return:
+	jr	$ra
diff --git a/2ano/2semestre/ac2/aula01/addicional-2.c b/2ano/2semestre/ac2/aula01/addicional-2.c
new file mode 100644
index 0000000..3dfd8af
--- /dev/null
+++ b/2ano/2semestre/ac2/aula01/addicional-2.c
@@ -0,0 +1,68 @@
+#include <detpic32.h>
+
+#define SIZE 20
+
+char *strcat(char *, char *);
+char *strcpy(char *, char *);
+int strlen(char *);
+int strcmp(char *str1, char *str2);
+
+int main(void) {
+    static char str1[SIZE + 1];
+    static char str2[SIZE + 1];
+    static char str3[2 * SIZE + 1];
+
+    printStr("Introduza 2 strings:\n");
+    readStr(str1, SIZE);
+    putChar('\n');
+    readStr(str2, SIZE);
+    putChar('\n');
+    printStr("Resultados:\n");
+    printStr("Str1 len: ");
+    printInt(strlen(str1), 10);
+    putChar('\n');
+    printStr("Str2 len: ");
+    printInt(strlen(str2), 10);
+    putChar('\n');
+    strcpy(str3, str1);
+    printStr("Str3 + Str2: ");
+    printStr(strcat(str3, str2));
+    putChar('\n');
+    printStr("Str1 == Str2: ");
+    printInt10(strcmp(str1, str2));
+    putChar('\n');
+    return 0;
+}
+// Returns the length of string "str" (excluding the null character)
+int strlen(char *str) {
+    int len;
+    for (len = 0; *str != '\0'; len++, str++);
+    return len;
+}
+// Copy the string pointed by "src" (including the null character) to
+// destination (pointed by "dst")
+char *strcpy(char *dst, char *src) {
+    char *p = dst;
+    for (; (*dst = *src) != '\0'; dst++, src++);
+    return p;
+}
+// Concatenates "dst" and "src" strings
+// The result is stored in the "dst" string
+char *strcat(char *dst, char *src) {
+    char *p = dst;
+    for (; *dst != '\0'; dst++);
+    strcpy(dst, src);
+    return p;
+}
+
+// Compares two strings, character by character
+// Returned value is:
+// < 0 string "str1" is "less than" string "str2" (first
+//      non-matching character in str1 is lower, in ASCII, than that of str2)
+// = 0 string "str1" is equal to string "str2"
+// > 0 string "str1" is "greater than" string "str2" (first
+//      non-matching character in str1 is greater, in ASCII, than that of str2)
+int strcmp(char *str1, char *str2) {
+    for (; (*str1 == *str2) && (*str1 != '\0'); str1++, str2++);
+    return (*str1 - *str2);
+}
diff --git a/2ano/2semestre/ac2/aula01/addicional-2.s b/2ano/2semestre/ac2/aula01/addicional-2.s
new file mode 100644
index 0000000..78ac89f
--- /dev/null
+++ b/2ano/2semestre/ac2/aula01/addicional-2.s
@@ -0,0 +1,223 @@
+	.equ	INKEY, 1
+	.equ	GETCHAR, 2
+	.equ	PUTCHAR, 3
+	.equ	READ_INT, 4
+	.equ	READ_INT10, 5
+	.equ	PRINT_INT, 6
+	.equ	PRINT_INT10, 7
+	.equ	PRINT_STR, 8
+	.equ	READ_STR, 9
+	.equ	EXIT, 10
+	.equ	READ_CORE_TIMER, 11
+	.equ	RESET_CORE_TIMER, 12
+
+	.equ	SIZE, 20
+
+	.data
+
+input:	.asciiz "Introduza 2 strings:\n"
+r_str:	.asciiz "Resultados:\n"
+res1:	.asciiz "Str1 len: "
+res2:	.asciiz "Str2 len: "
+res3:	.asciiz "Str3 + Str2: "
+res4:	.asciiz "Str1 == Str2: "
+
+str1:	.space	21
+str2:	.space	21
+str3:	.space	41
+
+	.text
+	.globl main
+
+main:
+	move	$s0, $ra		# Save $ra
+
+	la	$a0, input
+	li	$v0, PRINT_STR
+	syscall
+
+	la	$a0, str1
+	li	$a1, SIZE
+	li	$v0, READ_STR
+	syscall
+
+	li	$a0, '\n'
+	li	$v0, PUTCHAR
+	syscall
+
+	la	$a0, str2
+	li	$a1, SIZE
+	li	$v0, READ_STR
+	syscall
+
+	li	$a0, '\n'
+	li	$v0, PUTCHAR
+	syscall
+
+	la	$a0, r_str
+	li	$v0, PRINT_STR
+	syscall
+
+	la	$a0, res1
+	li	$v0, PRINT_STR
+	syscall
+
+	la	$a0, str1
+	jal	strlen
+	move	$a0, $v0
+	li	$a1, 10
+	li	$v0, PRINT_INT
+	syscall
+
+	li	$a0, '\n'
+	li	$v0, PUTCHAR
+	syscall
+
+	la	$a0, res2
+	li	$v0, PRINT_STR
+	syscall
+
+	la	$a0, str2
+	jal	strlen
+	move	$a0, $v0
+	li	$a1, 10
+	li	$v0, PRINT_INT
+	syscall
+
+	li	$a0, '\n'
+	li	$v0, PUTCHAR
+	syscall
+
+	la	$a0, str3
+	la	$a1, str1
+	jal	strcpy
+
+	la	$a0, res3
+	li	$v0, PRINT_STR
+	syscall
+	
+	la	$a0, str3
+	la	$a1, str2
+	jal	strcat
+	move	$a0, $v0
+	li	$v0, PRINT_STR
+	syscall
+
+	li	$a0, '\n'
+	li	$v0, PUTCHAR
+	syscall
+
+	la	$a0, res4
+	li	$v0, PRINT_STR
+	syscall
+
+	la	$a0, str1
+	la	$a1, str2
+	jal	strcmp
+	move	$a0, $v0
+	li	$v0, PRINT_INT10
+	syscall
+
+	li	$a0, '\n'
+	li	$v0, PUTCHAR
+	syscall
+
+	jr	$s0
+	
+
+
+#----------------------------------------------
+# STRLEN
+#----------------------------------------------
+# Mapa de registos
+# $a0	→ str
+# $t0	→ len
+# $t1	→ *str
+strlen:
+	li	$t0, 0
+strlen_loop:
+	lb	$t1, 0($a0)
+	beq	$t1, 0, strlen_return
+	addiu	$t0, $t0, 1
+	addiu	$a0, $a0, 1
+	j	strlen_loop
+strlen_return:
+	move	$v0, $t0
+	jr	$ra
+#----------------------------------------------
+
+#----------------------------------------------
+# STRCPY
+#----------------------------------------------
+# Mapa de registos
+# $a0	→ dst
+# $a1	→ src
+# $t0	→ p
+# $t1	→ *src
+strcpy:
+	move	$t0, $a0
+strcpy_loop:
+	lb	$t1, 0($a1)
+	sb	$t1, 0($a0)
+	beq	$t1, 0, strcpy_return
+	addiu	$a0, $a0, 1
+	addiu	$a1, $a1, 1
+	j	strcpy_loop
+strcpy_return:
+	move	$v0, $t0
+	jr	$ra
+#----------------------------------------------
+
+#----------------------------------------------
+# STRCAT
+#----------------------------------------------
+# Mapa de registos
+# $a0	→ dst
+# $a1	→ src
+# $t0	→ p
+# $t1	→ *dst
+strcat:
+	move	$t0, $a0
+strcat_loop:
+	lb	$t1, 0($a0)
+	beq	$t1, 0, strcat_return
+	addiu	$a0, $a0, 1
+	j	strcat_loop
+strcat_return:
+	addiu	$sp, $sp, -20
+	sw	$ra, 0($sp)
+	sw	$a0, 4($sp)
+	sw	$a1, 8($sp)
+	sw	$t0, 12($sp)
+	sw	$t1, 16($sp)
+	jal	strcpy
+	lw	$ra, 0($sp)
+	lw	$a0, 4($sp)
+	lw	$a1, 8($sp)
+	lw	$t0, 12($sp)
+	lw	$t1, 16($sp)
+	addiu	$sp, $sp, 20
+	move	$v0, $t0
+	jr	$ra
+#----------------------------------------------
+
+#----------------------------------------------
+# STRCMP
+#----------------------------------------------
+# Mapa de registos
+# $a0	→ str1
+# $a1	→ str2
+# $t0	→ *str1
+# $t1	→ *str2
+strcmp:
+	lb	$t0, 0($a0)
+	lb	$t1, 0($a1)
+	bne	$t0, $t1, strcmp_return
+	beq	$t0, 0, strcmp_return
+	addiu	$a0, $a0, 1
+	addiu	$a1, $a1, 1
+	j	strcmp
+strcmp_return:
+	sub	$v0, $t0, $t1
+	jr	$ra
+#----------------------------------------------