diff --git a/2ano/1semestre/ac1/aula04/AC1-P-Aula4.pdf b/2ano/1semestre/ac1/aula04/AC1-P-Aula4.pdf
new file mode 100644
index 0000000..b4c2056
Binary files /dev/null and b/2ano/1semestre/ac1/aula04/AC1-P-Aula4.pdf differ
diff --git a/2ano/1semestre/ac1/aula04/ex01-addicional.asm b/2ano/1semestre/ac1/aula04/ex01-addicional.asm
new file mode 100644
index 0000000..f360bfb
--- /dev/null
+++ b/2ano/1semestre/ac1/aula04/ex01-addicional.asm
@@ -0,0 +1,72 @@
+	.data
+	.eqv SIZE, 20
+	.eqv print_string, 4
+	.eqv read_string, 8
+str:	.space 21
+str1:	.asciiz "Introduza uma string: "
+
+	.text
+	.globl main
+
+# Mapa de registos
+# $t0:		p
+# $t1:		*p
+
+main:	li 	$v0, print_string
+	la	$a0, str1
+	syscall				# print_string("Introduza uma string: ");
+	
+	la	$a0, str
+	li	$a1, SIZE
+	li	$v0, read_string
+	syscall				# read_string(str, SIZE);
+
+# --- CONVERTER PARA MAIÚSCULAS ---
+
+	la	$t0, str		# p = str;
+
+while1:	lb	$t1, 0($t0)	
+	beq	$t1, 0x00, endw1	# while (*p != '\0') {
+
+if1:	blt	$t1, 0x61, else1	# if (*p >= 'a')
+	bgt	$t1, 0x7A, else1	# if (*p <= 'z')
+
+	addiu	$t1, $t1, -0x20		# *p = *p - 'a' + 'A';
+	sb	$t1, 0($t0)
+
+else1:	addiu	$t0, $t0, 1		# p++
+	j	while1			# }
+
+endw1:	li	$v0, print_string
+	la	$a0, str
+	syscall
+
+# ---------------------------------
+
+	li	$v0, 11
+	li	$a0, '\n'
+	syscall
+
+# --- CONVERTER PARA MINÚSCULAS ---
+
+	la	$t0, str		# p = str;
+
+while2:	lb	$t1, 0($t0)	
+	beq	$t1, 0x00, endw2	# while (*p != '\0') {
+
+if2:	blt	$t1, 0x41, else2	# if (*p >= 'a')
+	bgt	$t1, 0x5A, else2	# if (*p <= 'z')
+
+	addiu	$t1, $t1, 0x20		# *p = *p - 'a' + 'A';
+	sb	$t1, 0($t0)
+
+else2:	addiu	$t0, $t0, 1		# p++
+	j	while2			# }
+
+endw2:	li	$v0, print_string
+	la	$a0, str
+	syscall
+
+# ---------------------------------
+
+	jr	$ra
diff --git a/2ano/1semestre/ac1/aula04/ex01-addicional.c b/2ano/1semestre/ac1/aula04/ex01-addicional.c
new file mode 100644
index 0000000..ccaaf72
--- /dev/null
+++ b/2ano/1semestre/ac1/aula04/ex01-addicional.c
@@ -0,0 +1,40 @@
+#include <stdio.h>
+#define SIZE 20
+
+int main(void)
+{
+    static char str[SIZE+1];
+    char *p;
+
+    printf("Introduza uma string: ");
+    scanf("%s", str);
+    p = str;
+
+    /// CONVERTER PARA MAIÚSCULAS
+    while (*p != 0x00)
+    {
+        if (*p >= 0x61 && *p <= 0x7A)
+            *p = *p + -0x20;
+
+        p++;
+    }
+    ///
+
+    printf("%s\n", str);
+
+    p = str;
+
+    /// CONVERTER PARA MINÚSCULAS
+    while (*p != 0x00)
+    {
+        if (*p >= 0x41 && *p <= 0x5A)
+            *p = *p + 0x20;
+
+        p++;
+    }
+    ///
+
+    printf("%s\n", str);
+
+    return 0;
+}
diff --git a/2ano/1semestre/ac1/aula04/ex01-addicional.md b/2ano/1semestre/ac1/aula04/ex01-addicional.md
new file mode 100644
index 0000000..ae9f3cd
--- /dev/null
+++ b/2ano/1semestre/ac1/aula04/ex01-addicional.md
@@ -0,0 +1,17 @@
+# Alinea b)
+
+| p (\$t0)   | \*p (\$t1) |                     |
+|:----------:|:----------:|:--------------------|
+| 0x10010000 | 0x41       | Valores iniciais    |
+| 0x10010001 | 0x63       | Fim da 1ª iteração  |
+| 0x10010002 | 0x31       | Fim da 2ª iteração  |
+| 0x10010003 | 0x2D       | Fim da 3ª iteração  |
+| 0x10010004 | 0x70       | Fim da 4ª iteração  |
+| 0x10010005 | 0x72       | Fim da 5ª iteração  |
+| 0x10010006 | 0x41       | Fim da 6ª iteração  |
+| 0x10010007 | 0x74       | Fim da 7ª iteração  |
+| 0x10010008 | 0x69       | Fim da 8ª iteração  |
+| 0x10010009 | 0x63       | Fim da 9ª iteração  |
+| 0x10010010 | 0x61       | Fim da 10ª iteração |
+| 0x10010011 | 0x53       | Fim da 11ª iteração |
+| 0x10010012 | 0x00       | Fim da 12ª iteração |
diff --git a/2ano/1semestre/ac1/aula04/ex01.asm b/2ano/1semestre/ac1/aula04/ex01.asm
new file mode 100644
index 0000000..05763a1
--- /dev/null
+++ b/2ano/1semestre/ac1/aula04/ex01.asm
@@ -0,0 +1,39 @@
+        .eqv SIZE,20
+        
+        .data
+str:    .space  21
+
+        .text
+        .globl main
+
+# Mapa de registos
+# num:      $t0
+# i:        $t1
+# str:      $t2
+# str+i:    $t3
+# str[i]:   $t4
+
+main:   la      $a0,str
+        li      $a1,SIZE
+        li      $v0,8
+        syscall                 # read_string(str,SIZE)
+        li      $t0,0           # num = 0
+        li      $t1,0           # i = 0
+
+while:  la      $t2,str         # $t2=&str[0] <=> $t2=str
+        addu    $t3,$t2,$t1     # $t3=&str[i] <=> $t3=str+i
+        lb      $t4,0($t3)      # $t4=str[i]
+        beq     $t4,'\0',endw   # if (str[i]=='\0') goto endw
+
+if:     blt     $t4,'0',endif
+        bgt     $t4,'9',endif
+        addi    $t0,$t0,1       # num++
+
+endif:  addi    $t1,$t1,1       # i++
+        j       while
+
+endw:   move    $a0,$t0
+        li      $v0,1
+        syscall
+
+        jr      $ra
diff --git a/2ano/1semestre/ac1/aula04/ex01.md b/2ano/1semestre/ac1/aula04/ex01.md
new file mode 100644
index 0000000..55d3aab
--- /dev/null
+++ b/2ano/1semestre/ac1/aula04/ex01.md
@@ -0,0 +1,13 @@
+# Alinea b)
+
+| Endereço de str (\$t2) | Endereço de str[i] (\$t3) | str[i] (\$t4) | i (\$t1) | num (\$t0) |  |
+|:-:|:-:|:-:|:-:|:-:|:-:|
+|            |            |            | 0 | 0 | Val. iniciais      |
+| 0x10010000 | 0x10010000 | 0x00000041 | 1 | 0 | Fim da 1ª iteração |
+| 0x10010000 | 0x10010001 | 0x00000043 | 2 | 0 | Fim da 2ª iteração |
+| 0x10010000 | 0x10010003 | 0x00000031 | 3 | 1 | Fim da 3ª iteração |
+| 0x10010000 | 0x10010003 | 0x0000002d | 4 | 1 | Fim da 4ª iteração |
+| 0x10010000 | 0x10010004 | 0x0000004c | 5 | 1 | Fim da 5ª iteração |
+| 0x10010000 | 0x10010005 | 0x00000061 | 6 | 1 | Fim da 6ª iteração |
+| 0x10010000 | 0x10010006 | 0x00000062 | 7 | 1 | Fim da 7ª iteração |
+| 0x10010000 | 0x10010006 | 0x00000073 | 8 | 1 | Fim da 8ª iteração |
diff --git a/2ano/1semestre/ac1/aula04/ex02.asm b/2ano/1semestre/ac1/aula04/ex02.asm
new file mode 100644
index 0000000..9b05a3f
--- /dev/null
+++ b/2ano/1semestre/ac1/aula04/ex02.asm
@@ -0,0 +1,38 @@
+        .eqv SIZE,20
+        
+        .data
+str:    .space  21
+
+        .text
+        .globl main
+
+# Mapa de registos
+# num:		$t0
+# p:		$t1
+# *p:		$t2
+
+main:   la      $a0,str
+        li      $a1,SIZE
+        li      $v0,8
+        syscall                 # read_string(str,SIZE)
+        
+	li      $t0,0           # num = 0
+	la	$t1, str	# p = str
+
+
+while:  lb	$t2, 0($t1)	# *p
+	beq	$t2, '\0', endw # while (*p != '\0') {
+
+if:	blt	$t2, '0', endif	# if (*p >= '0')
+	bgt	$t2, '9', endif # if (*p <= '9')
+	addi	$t0, $t0, 1	# num++;
+
+endif:  addiu	$t1, $t1, 1	# p++;
+	j 	while		# }
+        
+
+endw:   move    $a0,$t0
+        li      $v0,1
+        syscall
+
+        jr      $ra
diff --git a/2ano/1semestre/ac1/aula04/ex02.md b/2ano/1semestre/ac1/aula04/ex02.md
new file mode 100644
index 0000000..c32b6c6
--- /dev/null
+++ b/2ano/1semestre/ac1/aula04/ex02.md
@@ -0,0 +1,14 @@
+# Alinea b)
+
+| num (\$t0) | p (\$t1)   | \*p (\$t2) |                    |
+|:----------:|:----------:|:----------:|:-------------------|
+| 0          | 0x10010000 | 0x41       | Val. iniciais      |
+| 0          | 0x10010001 | 0x43       | Fim da 1ª iteração |
+| 0          | 0x10010002 | 0x31       | Fim da 2ª iteração |
+| 1          | 0x10010003 | 0x2D       | Fim da 3ª iteração |
+| 1          | 0x10010004 | 0x4C       | Fim da 4ª iteração |
+| 1          | 0x10010005 | 0x41       | Fim da 5ª iteração |
+| 1          | 0x10010006 | 0x42       | Fim da 6ª iteração |
+| 1          | 0x10010007 | 0x73       | Fim da 7ª iteração |
+| 1          | 0x10010008 | 0x00       | Fim da 8ª iteração |
+
diff --git a/2ano/1semestre/ac1/aula04/ex03-c.asm b/2ano/1semestre/ac1/aula04/ex03-c.asm
new file mode 100644
index 0000000..cbf5d06
--- /dev/null
+++ b/2ano/1semestre/ac1/aula04/ex03-c.asm
@@ -0,0 +1,34 @@
+	.data
+	.eqv SIZE, 4
+	.eqv print_int10, 1
+array:	.word 7692, 23, 5, 234
+
+	.text
+	.globl main
+
+# Mapa de registos
+# $t0:		i
+# $t1:		soma
+# $t2:		array
+# $t3:		array[i]
+
+main:	li	$t1, 0			# int soma = 0;
+	li	$t0, 0			# int i = 0;
+	la	$t2, array
+
+while:	bge	$t0, SIZE, endw		# while (i < SIZE) {
+	
+	sll	$t4, $t0, 2
+	addu	$t3, $t2, $t4
+	lw	$t3, 0($t3)
+
+	add	$t1, $t1, $t3
+
+	addi	$t0, $t0, 1
+	j while
+
+endw:	li	$v0, print_int10
+	move	$a0, $t1
+	syscall
+
+	jr	$ra
diff --git a/2ano/1semestre/ac1/aula04/ex03-c.c b/2ano/1semestre/ac1/aula04/ex03-c.c
new file mode 100644
index 0000000..7a8560b
--- /dev/null
+++ b/2ano/1semestre/ac1/aula04/ex03-c.c
@@ -0,0 +1,18 @@
+#include <stdio.h>
+#define SIZE 4
+int array[4] = {7692, 23, 5, 234};
+
+int main(void)
+{
+    int soma = 0;
+    int i = 0;
+
+    while (i < SIZE) {
+        soma += array[i];
+        i++;
+    }
+
+    printf("%d", soma);
+
+    return 0;
+}
diff --git a/2ano/1semestre/ac1/aula04/ex03.asm b/2ano/1semestre/ac1/aula04/ex03.asm
new file mode 100644
index 0000000..5efcb0e
--- /dev/null
+++ b/2ano/1semestre/ac1/aula04/ex03.asm
@@ -0,0 +1,35 @@
+	.data
+	.eqv SIZE, 4
+	.eqv print_int10, 1
+array:	.word 7692, 23, 5, 234
+
+	.text
+	.globl main
+
+# Mapa de registos
+# $t0:		p
+# $t1:		pultimo
+# $t2:		*p
+# $t3:		soma
+
+main:	li	$t3, 0			# int soma = 0;
+	
+	la	$t0, array		# p = array;
+
+	li	$t4, SIZE
+	addi	$t4, $t4, -1
+	sll	$t4, $t4, 2
+	la	$t1, array		# pultimo = array;
+	addu	$t1, $t1, $t4		# pultimo += size - 1;
+
+while:	bgt	$t0, $t1, endw		# while (p <= pultimo) {
+	lw	$t2, 0($t0)		# *p
+	add	$t3, $t3, $t2		# soma += (*p);
+	addiu	$t0, $t0, 4		# p++;
+	j while
+
+endw:	li	$v0, print_int10
+	move	$a0, $t3
+	syscall				# print_int10(soma);
+
+	jr	$ra
diff --git a/2ano/1semestre/ac1/aula04/ex03.md b/2ano/1semestre/ac1/aula04/ex03.md
new file mode 100644
index 0000000..2f50c7f
--- /dev/null
+++ b/2ano/1semestre/ac1/aula04/ex03.md
@@ -0,0 +1,9 @@
+# Alinea b)
+
+| p (\$t0)   | pultimo (\$t1) | \*p (\$t2) | soma (\$t3) |                    |
+|:----------:|:--------------:|:----------:|:-----------:|:-------------------|
+| 0x10010000 | 0x1001000C     | 0x0000     | 0x0000      | Val. iniciais      |
+| 0x10010004 | 0x1001000C     | 0x1E0C     | 0x1E0C      | Fim da 1ª iteração |
+| 0x10010008 | 0x1001000C     | 0x0017     | 0x1E23      | Fim da 2ª iteração |
+| 0x1001000C | 0x1001000C     | 0x0005     | 0x1E28      | Fim da 3ª iteração |
+| 0x10010010 | 0x1001000C     | 0x00EA     | 0x1F12      | Fim da 4ª iteração |