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class Mutex:
    fun lock():
      pass
    fun unlock():
      pass

class ConditionVariable:
    fun wait(mutex):
      # lock the variable 
    fun notify_all(mutex):

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.DATA
    ADDR_7SEG       EQU 02H   ; 2 Decimal
    
    ; 7-Segment Encoding Table (Common Cathode)
    ; Maps index 0-F to segment patterns (gfedcba)
    HEX_TABLE
        DB 
            3FH, ; 0 
            06H, ; 1
            5BH, ; 2

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.DATA
    ADDR_LEDS       EQU 12H   ; 18 Decimal (Address of the 74x373 Latch)
    
    ; Shadow variable to store current state of LEDs (initially all OFF)
    LED_SHADOW      DB  0FFH   

    ; Bit Definitions for LEDs (0 to 7 - one hot encoded)
    LED0_MASK       EQU 01H   ; 0000 0001B
    LED1_MASK       EQU 02H   ; 0000 0010B
    LED2_MASK       EQU 04H   ; 0000 0100B

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.DATA
    ADDR_KBD_IN     EQU 16H   ; 22 Decimal
    ADDR_KBD_OUT    EQU 18H   ; 24 Decimal

    ; Column Selection Masks (Active Low)
    COL_1_MASK      EQU 11111110B ; Select Column 1
    COL_2_MASK      EQU 11111101B ; Select Column 2
    COL_3_MASK      EQU 11111011B ; Select Column 3

    ; Row Input Masks have a 1 hot encoding because TEST does bitwise AND comparing the result with "0"

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.DATA
    ; Port Addresses
    ADDR_8255_A     EQU 0250H
    ADDR_8255_C     EQU 0254H
    ADDR_8255_CTRL  EQU 0256H

    ; Strobe: 1 (Idle) -> 0 (Trigger) -> 1 (Idle)
    STROBE_IDLE     EQU 01H   ; Bit 0 is 1
    STROBE_ACTIVE   EQU 00H   ; Bit 0 is 0

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.DATA
    ADDR_8251_CTRL  EQU 04D0H
    ADDR_8251_DATA  EQU 04D2H

    ; Status Masks
    MASK_TXRDY      EQU 00000001B ; Bit 0 is TxRDY (Transmitter Ready)
    MASK_RXRDY      EQU 00000010B ; Bit 1 is RxRDY (Receiver Ready)

.CODE

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.DATA
    ADDR_8255_CTRL  EQU 0256H   ; Control Register Address
    
    ; Control Word for 8255: 
    ; Bit 7=1 (Mode Set Flag)
    ; Bit 6-5=00 (Group A Mode 0 - Basic I/O)
    ; Bit 4=0 (Port A = Output)
    ; Bit 3=0 (Port C Upper = Output)
    ; Bit 2=0 (Group B Mode 0)
    ; Bit 1=1 (Port B = Input - Common default)

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#include <iostream>
#include <cstring>

using namespace std;

char vowels[] = {'a', 'e', 'i', 'o', 'u'};


char *last_vowel(char* sentence) {
    char* last_vowel_found;