SIMULADOR ASSEMBLER DE 8 BITS - SET DE INSTRUCCIONES DE 8 BITS - SIMPLE 8-BIT ASSEMBLY SIMULATOR
Summary
TLDREste video presenta un simulador de ensamblador de 8 bits, que permite manipular datos de 8 bits y comprender su conjunto de instrucciones. Se explica la organización de una computadora, destacando la CPU con sus registros y la unidad de control, así como la memoria RAM en hexadecimal. Seguidamente, se explora la sintaxis del ensamblador, incluyendo etiquetas, comentarios, formatos de datos y registros generales de uso. Se detallan las instrucciones del conjunto de instrucciones, como movimiento, matemáticas, lógicas, saltos y llamadas a funciones, y cómo se ejecutan en el simulador. El ejemplo final muestra cómo imprimir 'Hello World' utilizando el simulador, pasando caracteres al output y utilizando la pila para almacenar valores temporales.
Takeaways
- 😀 Este video trata sobre el uso de un simulador de ensamblador de 8 bits, que permite manipular datos de 8 bits y ejecutar un conjunto limitado de instrucciones.
- 🔧 Se solicita a los espectadores que se suscriban y den like al video para apoyar la creación de más contenido similar.
- 💻 El simulador representa una computadora básica con una CPU compuesta por registros y una unidad de control, así como una memoria RAM que se muestra en hexadecimal.
- 📝 Se explican los diferentes tipos de registros, incluyendo registros generales (A, B, C, D), el registro de programa (IP) y el puntero de pila (SP).
- 📌 Se destacan las banderas o flags que indican condiciones para las instrucciones del programa, como el flag de cero (Z) y el flag de carry (C).
- 🛠️ Se presenta una sencilla sintaxis de ensamblador, incluyendo la definición de constantes y la manipulación de memoria y registros.
- ⏯️ El simulador incluye un botón 'Run' para ejecutar programas, 'Reset' para reiniciar y la capacidad de depurar paso a paso.
- 🔢 Se describen las diferentes instrucciones y sus formatos, como movimientos (mov), matemáticas (ad, sub), incremento/decremento (inc, dec), y operaciones lógicas (and, or, xor, not).
- 🔄 Se mencionan las instrucciones de salto (jmp, jz, jnz) y cómo funcionan con las banderas para controlar el flujo del programa.
- 📡 Se explica cómo se manejan las instrucciones de impresión y salida, utilizando la memoria y los registros para enviar datos al output.
- 🏁 El video culmina con un ejemplo de cómo se programa el simulador para imprimir 'Hello World', utilizando ciclos, saltos condicionales y manejo de la pila.
Q & A
¿Qué es un simulador de ensamblador de 8 bits?
-Un simulador de ensamblador de 8 bits es una herramienta que simula la funcionalidad de una CPU de 8 bits, permitiendo manipular datos de 8 bits y ejecutar un conjunto limitado de instrucciones.
¿Cuál es la función de los registros en un simulador de ensamblador?
-Los registros en un simulador de ensamblador son componentes de la CPU que almacenan datos y direcciones, incluyendo registros generales (A, B, C, D), el registro de programa (IP) y el puntero de pila (SP).
¿Qué son las banderas o flags en un simulador de ensamblador y cuáles son algunos ejemplos?
-Las banderas o flags son indicadores que representan condiciones en el procesador, como el flag de cero (Z), el flag de carry (C) y el flag de overflow (F), que se utilizan para tomar decisiones en programas de bajo nivel.
¿Cómo se representa la memoria en el simulador y qué tipo de memoria se utiliza?
-La memoria en el simulador se representa en hexadecimal, con células de 8 bits cada una. Se utiliza RAM para almacenar datos y instrucciones en el simulador.
¿Qué es la instrucción 'MOV' en el contexto del simulador de ensamblador y cómo se utiliza?
-La instrucción 'MOV' se utiliza para mover datos entre registros o entre registros y memoria. Tiene diferentes modos de direccionamiento y puede mover valores de memoria a registros, de registros a memoria, o cargar constantes en registros.
¿Qué son los modos de direccionamiento y cómo afectan la ejecución de instrucciones en el simulador?
-Los modos de direccionamiento definen cómo se interpretan los operandos en las instrucciones. Pueden ser directos, indirectos, con desplazamiento o relativos, y determinan cómo se accede a los datos en la memoria.
¿Cuál es la diferencia entre las instrucciones 'INC' y 'DEC' en el simulador?
-Las instrucciones 'INC' (incremento) y 'DEC' (decremento) se utilizan para aumentar o disminuir respectivamente el valor de un registro en uno. Estas instrucciones modifican el flag de cero (Z) si el resultado es cero.
¿Cómo se implementan las operaciones lógicas en el simulador y cuáles son algunos ejemplos?
-Las operaciones lógicas, como AND, OR y XOR, se implementan a través de instrucciones que realizan operaciones bit a bit entre registros, memoria o constantes. Estas operaciones son fundamentales para la manipulación y comparación de datos en un nivel bajo.
¿Qué son las instrucciones de salto y cómo funcionan en el simulador de ensamblador?
-Las instrucciones de salto, como 'JMP' para saltos incondicionales y saltos condicionales basados en flags, permiten cambiar la secuencia de ejecución de las instrucciones. Esto es fundamental para controlar el flujo del programa.
¿Cómo se representa la salida de datos en el simulador y cómo se relaciona con la memoria?
-La salida de datos en el simulador se representa en una zona de memoria mapeada, generalmente en una dirección específica como E8 a FF. Los datos enviados a esta área se consideran la salida del programa.
Outlines
💻 Introducción al simulador de ensamblador de 8 bits
Este primer párrafo presenta un video que explora un simulador de ensamblador de 8 bits. El simulador maneja datos de 8 bits y tiene un conjunto limitado de instrucciones. Se invita al espectador a suscribirse y a dar like para apoyar la creación de contenido similar. El video se centra en la simulación de una computadora, explicando la organización de las diferentes unidades funcionales como la CPU, que incluye registros y una unidad de control, y la memoria RAM representada en hexadecimal. Se menciona la importancia de las etiquetas para las instrucciones de ensamblaje, la salida de datos básica y la interconexión de todos los componentes.
📝 Análisis detallado del conjunto de instrucciones y registros
En este segundo párrafo, el presentador analiza las instrucciones y registros del simulador. Se discuten los registros generales de uso como A, B, C, D, el registro de programa IP y el puntero de pila SP. También se explican los códigos de condición Z, C y F. Seguidamente, se examina la memoria limitada, la velocidad de procesamiento y la sintaxis de las instrucciones, incluyendo la manipulación de diferentes formatos numéricos y la asignación de constantes y direcciones.
🔢 Operaciones matemáticas y lógicas en ensamblador
El tercer párrafo se enfoca en las operaciones matemáticas y lógicas que puede realizar el simulador. Se describen las instrucciones para la adición, la resta, el incremento y la decremento de registros, así como las multiplicaciones y divisiones. También se mencionan las instrucciones lógicas de AND, OR y NOT, y las instrucciones de desplazamiento. Se explica cómo se utilizan los registros y las direcciones para estas operaciones, y se ofrecen detalles sobre la ejecución de saltos y llamadas a funciones.
📑 Ejemplo práctico: Imprimir 'Hello World' con el simulador
Este párrafo presenta un ejemplo práctico de cómo utilizar el simulador para imprimir 'Hello World'. Se detalla cómo se almacenan las cadenas de caracteres en la memoria y cómo se ejecutan las instrucciones para enviar cada carácter a la salida. Se explica el uso de etiquetas, constantes y la manipulación de registros para dirigir la salida. El ejemplo incluye una descripción de cómo se ejecutan las rutinas de impresión y cómo se gestiona el ciclo de impresión hasta que se encuentra el término de la cadena.
🔁 Ciclo de ejecución y finalización del programa
El quinto párrafo describe el ciclo de ejecución del programa de impresión 'Hello World' y cómo se lleva a cabo la finalización del mismo. Se detalla cómo se utilizan las instrucciones de salto condicional y la bandera de cero para controlar el ciclo de impresión. Se ilustra la ejecución de la rutina de impresión, la manipulación de registros y la gestión del puntero de pila para completar la impresión de la cadena. Finalmente, se menciona cómo se limpia la pila y se detiene la ejecución del programa.
👋 Conclusión y despedida
El último párrafo del guion del video ofrece una conclusión y despedida al espectador. Se resalta que este video fue un acercamiento inicial al simulador de 8 bits y se sugiere que en futuras entregas se profundizará más en el tema. Se agradece la atención y se invita a los espectadores a seguir explorando el contenido.
Mindmap
Keywords
💡Ensamblador
💡Simulator
💡Registros
💡Instrucciones
💡Memoria
💡Etiquetas
💡Pila
💡Flags
💡Ciclo de reloj
💡Subrutina
Highlights
Introducción a un simulador de ensamblador de 8 bits.
Explicación de la estructura del simulador y sus componentes.
Descripción de las diferentes unidades funcionales del CPU.
Importancia de los registros y flags en la ejecución de programas.
Función de la memoria RAM en el simulador.
Uso de etiquetas y direcciones de memoria para instrucciones en ensamblador.
Descripción de los registros de uso general y específico.
Explicación de los diferentes tipos de flags y su rol.
Visualización de la memoria y su representación en hexadecimal.
Introducción al código de instrucciones y su análisis.
Descripción de la sintaxis y formatos de datos en ensamblador.
Métodos para trabajar con diferentes formatos numéricos en ensamblador.
Importancia de los registros generales y específicos en las operaciones.
Detalles sobre los diferentes formatos de instrucciones y direccionamiento.
Análisis de la constante de 0 a 255 y su uso en memoria.
Descripción de las instrucciones básicas de movimiento y operaciones matemáticas.
Uso de instrucciones de incremento y decremento en registros.
Funciones de las instrucciones de multiplicación y división.
Introducción a las instrucciones lógicas y su aplicación.
Detalles sobre las instrucciones de desplazamiento y su funcionamiento.
Uso de instrucciones de comparación y saltos incondicionales.
Descripción de los saltos condicionales y su dependencia de flags.
Función de las instrucciones de llamada a funciones y manejo de subrutinas.
Uso de instrucciones PUSH y POP para manipular la pila.
Finalización de la ejecución con la instrucción HLT.
Ejemplo de programa que imprime 'Hello World' utilizando el simulador.
Análisis del flujo del programa y su ejecución paso a paso.
Explicación de cómo se manejan los caracteres y la salida en el simulador.
Resumen de la funcionalidad del simulador y lo que se puede aprender de él.
Transcripts
Welcome to another video in this case we are going to be working with an
8-bit assembler simulator, a simulator that is going to have basically 8-bit data to manipulate quite
simply in terms of its set of instructions and we are going to see basically its its its set
analyze its instructions and see this example before starting I ask you to hit the
subscribe button and I like it since it helps me a lot to be able to continue creating this type of videos and we are going
to start well what we have here notice that eh basically It is going to simulate precisely
a computer. We have seen in other videos the organization of the computer where we have
separated it into different functional units, basically, where we always have what is the cpu,
which is made up of a series of registers, a control unit, several registers.
general use and specific use at the same time We also have different types of Flags or flags that
will allow us to say basically have the conditionals or the condition codes of the
different programs that are running at a low level on the other hand we will have the memory unit
as we see here we are going to have the RAM memory in this case notice that we are seeing it in
hexadecimal where we have the different digits or cells of exactly 8 bits in this case we are going
to have here in this part the labels for what the instructions are at a low level for
what is the assembly that we are going to see here and of course we have just one data output
basically we have a basic computer, worth the redundancy with just input output
cpu memory and obviously all this all this interconnected on the other hand we are going to have
what is the code part of the Instruction Code here we have a simple example that
this simulator brings we see that we have the Run button to run the program reset it and see the
step by step to be able to debug the step by step of what is happening We have To take into account and
basically analyze what we have in each part of this simulator we see that we have several registers
where we have general use registers such as A, B, C and D. We have here what
is the IP register, which is specific use, this IP is also known as a program counter,
program Counter, which basically marks the sequence of instructions that is being executed.
On the other hand, we have the stack Pointer, which is the stack pointer that will
basically mark where we have that stack of memory to be able to use it in different aspects of
the low-level programs that we are going to develop. On the other hand, we have Z, c,
and F, which are the different condition codes, for example, Z, if any value gives us zero,
c, which is going to be the carry of the sum and the F eh that is going to indicate to us, let's say the different
values that we are now going to see in the in the instruction set, well, look at the memory, we have a
series of limited memory positions, we have the stack Pointer that is being marked Here in this
memory area we have the clock speed also to see, let's say the
processing speed in Herz that our program will have when it runs. For example, if we
put Run we see there that it is being executed in a series of let's say of this 4
hz cycle and then obviously we can change the speed of execution well before we
see that it is executing before analyzing this code we are going to continue analyzing the set of
instructions for that we are going to go to the part of the instruction set that we have here and we see
that we can analyze a little the syntax that this instructions are going to have. This
assembler language, notice that the simulator consists of an 8-bit cpu with 256 by of memory. Let's all
say obviously we have instructions and codes, the variables that are going to be used or loaded into
memory, as we were seeing, we have to see that the operands to simplify each instruction
and operand are from one byte and the move instructions are going to use 3 bytes in memory. Yes, notice that
we have different sizes of instructions there that will to have this set well on the other hand notice
that the output the console output is going to be mapped in what is the address e8 enimal to the ff
which was that space that we were just seeing that now we are going to continue working on it
Well, in terms of syntax, we have the Labels that will basically allow us to mark
the different instructions that we are going to have in our assembly code,
we are going to be able to comment with the semicolon to leave a comment on each of those. lines and
then we have what the data formats are. Notice that we can work in decimal
basically by placing a number in decimal if we want it there, also label and with the d to
indicate that it is a decimal number, the same if we want to work with a binary Notice we have
10 the amos label with the B for to work on that in that format and generally we are going to be
working with hexadecimal yes notice that it is going to be represented as 0x and the hexadecimal as 4
as an example We also have to work in octal that is We have several formats to be able to
work in this processing. On the other hand, we have the characters. Notice that here we have the character a.
The String with double quotes is basically going to be delimited with single quotes like Hello
Word here, and then we have to go into what the general purpose registers to work
with the operands there we said that we had the general purpose registers such as
abc and d we will be able to save any address value that we are going to use the stack
Pointer which is the scp as we were talking about today and then how are they going to be Use the different
directions of those instructions. If you don't know what the format of the instructions is like,
I leave you the video where we see various instruction formats with various directions and where
we also work with the basic format so you can understand a little more about the design. of
a processor and you can understand even more what we are talking about at a low level, in
this case talking about the addresses and the operands or the operation codes of the
instructions, well notice that we basically have how the instructions are going to be used. different addresses
can be a register can be a register with an offset with a negative
and positive offset reference or relative to the program Counter or relative to a relative also to a
register addressing issues whether relative to the proun relative to a register goes based on
the addressing mode of how it is addressed in memory if you do not know what
this topic is like, I also leave you the video so that you can review it. Note that
to work with the assembly we need several various theories to understand various concepts
and theories of What is the design of the processor? To have an idea of the background that each
of these instructions has or the design of a set of instructions, notice that the constants are going
to go from 0 to 255. We also have the addresses using the Labels, which are obviously going to be marked. in memory
where that Label or that function that is going to be executed is going to be found and well the good ones. Let's go to the
best known instructions in this case it is the one that is going to copy a value somewhere in this case
where we indicate and here where Enter the addressing modes again where we are going to see
that here we have an operation code, for example the moov, and then we have two operands that in
this case are register by register, the registers can be a register address. Remember that
they are abcyd and a memory address. of that 256 byte space that marked us in this in
this part of the memory so notice it says that we could be working on moving a
memory value to a register value, moving a value from one register to another register or saving
a constant In a register, in turn, we can also move from a register to a
memory address and a constant to a memory address. These are the actions that this set
of instructions allows us to define a constant. We are going to use this db syntax to define that
value. constant after below for the Mathematical operations whether it is the addition
the addition or the subtraction the subtraction notice that also in the case of what is the
operation code we are going to have there the ad or the sub and then the operands where we have record a
register register to memory address register to constant both for addition and also for
what is subtraction or subtraction to work with the increment of register If we want to use
Let's say a register that we can define as a zero value and we want it to be incremented, we are going
to use Inc or dec to decrement that register, what will it be modifying in the event that it reaches
zero, for example, I could be modifying the Flags, the zero flag as we mentioned
today Note that the SP can use inco-decrement operations to be, let's say, saving
values in a stack in memory for multiplication and division. Note that
in this case it requires a single operand. We are going to multiply with a register or we can
basically multiply the value of the address. or multiply a constant on the other hand we have the
division there also for register for for memory address and for constant we have
logical instructions either an or x or y not are the basic ones yes remember the exclusive x or or are widely
used to make comparisons low level with obviously at the binary level s different
functions of an to be able to mask different binary values for example So we have
all those instructions also to use We also have the shift instructions to be able to
move or rotate, let's say the values from one register to another, notice that basically we can
there have those are those shift left and shift right movements with two operands register register
register memory address and constant register on the other hand we are going to have the
cmp or comp instructions to compare uh two register values or values between register and memory
or value between register and constant, notice that these are the combinations that can be used
for the operands in this case. Then we have the champs or jump instructions in which
we have the J, which is an unconditional jump, that is, it will always jump to an address. specific
when this instruction is executed or the conditional jumps which may be working
with those condition values or the Flags that we were talking about may be, let's say, reading
a flag to precisely verify whether it jumps or not jumps and those flags are going to be modify based on
conditions that may occur in the different mathematical or logical operations that
are carried out on the data, then those jamps are those jamps when they are being executed they will
be reading those Flags or modifying those Flags to jump conditionally in the case so that
this condition is met, yes, notice that we have several, obviously they are going to be used as
they are needed in a particular program. On the other hand, we have the calls for the functions
for addresses, eh, which will indicate, let's say where to call a function to jump to a subroutine
within what is the program the red instruction to be able to exit a subroutine and then
finally the last three instructions Push from a register of an address or a constant
to place in what is the address of the stack Pointer yes are registers or are instructions
which, notice that the addressing is implicit since it is going to place the value
of the constant address register in the stack Pointer that indicates precisely the
SP register, different are the other instructions where we have several, for example, notice we have several
operands where it means that we are going to make an an between register and register and we are going to save
the value in the first register, we are telling you where we are going to save the value but
in the case of The Push or the pop that is to get out of the stack For example Push to place the pop
to remove implicitly it will go to the stack Pointer to the address marked by the stack Pointer which is
the one we saw at the beginning on the other hand and finally the last instruction that we are going to
use is hlt the halt to to be able to finalize the processor, having said this and analyzing the set of
instructions, we can just go back to what the simulator is and see the example that we were
seeing at the beginning. Well, let's see then the example that we have here. Look, there we have the
comitas for the comments. simple example simple write Hello World to the output that is, it is going to
write hello world in the output and notice that it is going to start with a jump Start we are going to have here a
Hello label that is going to obviously mark those labels the beginning where we are going to keep
eh basically a variable a constant in this case it is called Hello World and also what
is a terminator yes remember that at a low level we have to go through each of the String
character by character and we have to basically tell it when that character ends
So notice that Hello Hello World is saved and then the constant eh zero to indicate
That that completion we have a Start label, notice that the program in the first instruction
is jump Start, that is, it will come here to jump to the first label, the first routine and this routine
will to mark the main routine of the system where we are going to move the Hello or the pointer actually of
the word Hello Yes in the c register that we have here F we are doing the reading directly
from the code and we are going to uh basically put the pointer to the output which in this case is 232 to
the register d which is this one here and then what we are going to do is call print which is the subroutine
to print exactly or to send the characters to the output to the output of
the stack remember that the stack the stack Pointer starts from e7 And that goes from the stack
Pointer forwards up we have the output so everything we send here in
memory is going to go towards the output so notice that we are going to do a Push a and then Push by
we are going to move the value B, let's say the value oab in this case, and then the Stop, the Stop of
the execution. Yes, well, then we have a Loop, that Loop is going to be, let's say masters, eh, calling
there in the program, in the main program where we are going to be. just moving the
character pointer towards the variable a so that it is then called by the Push towards the output and
then we are going to move the value, let's say of a towards the value d in order to be able to write towards the output, c and
d will be incremented to go towards a register towards a, let's say towards a higher address
where this string is stored and then B will be compared with C to find out if
the variable zero is in B to finish that cycle in which it will be
printing all the values towards the output, don't notice that we have the pop by the
pop a, we are going to execute this, we are going to see what happens, notice that
the print routine is executed there and then the Loop enters, print is executed and enters In the Loop, that is, it will
end and it will move the values towards the output. Notice that there it is just moving
everything towards the output and Hello World will appear. Note that the instructions are saved and
stored in memory, we can reset it and do The step by step begins in Start. Notice
that here we are basically going to have stored the word Hello Hello World, yes, and the 00, which
is the constant, is the first thing we are going to have in memory and then the instructions appear. Notice
that the first instruction in this case It will be precisely the Hello mod, which is what will be
executed, then the second instruction will be here, the IP will go to us, it will
basically indicate where it begins and where it continues, where the next instruction goes, this
will be the movement of the exit pointer towards D, then notice that e8 is
the exit pointer, so from e8 forward we are going to go towards the outside
and 02 is precisely where the word yes begins, where our string
of characters begins, notice We have 00, 01 and 02 where it will start, there it is the pointer
of the output. So now call the print function, it will come to here, print has all
these instructions, so look, Push a, that is, place 17 at the output. In this
case, notice that it executes Push C zero has nothing and every time a Push is executed
what happens is that the value of the lsp basically decreases if Push is executed Push
B The value decreases and now it is moves to moves the value of zero then there
it begins, let's say basic, the reading of each of the characters was prepared here basically
the Push a and the Push B to start making let's say the output of these values So
look at the following, the first value What is going to be moved is the pointer from c to register a,
so notice that what this indicates is that the content of address C, which is 02, is going to be moved.
move to the value a then notice that 48 in this direction the address of c The value of
a was moved once the value of a is moved what is going to happen next is writing to the output So
the value of a is going to go away towards the address e8, yes, e8 is the address we have here that indicates
the output, so the content of D is e8, which means that we are addressing according to the content
of D directly and the content of a will be sent to the value at the output of to that address which
is e8, notice that 48 was sent to e8 C is incremented to indicate that we are going to go to the next character
and d is incremented to indicate that we are going to go to the next output address so then
notice ca 03 is incremented increments da e9 And we have the Loop Yes As long as the register or
basically Z is not different from zero we are going to return to the cycle yes look here compare And if
yes until it is zero it will continue in the cycle then it comes back to move the character towards
a moved 65 towards yes, notice that there the first character came out the output which is 48 now we have to
take the e the e is the 65 that is now in a in D let's take it to the output it goes to the output
65 And now it came out and we increment C to continue to 6c in hexadecimal. Look, we increment C is going
to point to 04, since 04 is this value and the stack Pointer is going to be marked if at 04, which is
where n4 Sorry, where is the next output going to go, sorry. the stack poter not the record d that na
would be this one from here where the six is going to come out the 6c that is going to happen now it is compared it comes back again and
just takes it to the exit Yes there it comes out in the movements to go to the exit move
the different characters and here notice that this is a cycle where until it finds
the value zero Yes until until until the moment that the jnz the conditional jump reaches zero Yes
As long as it is not zero it jumps when it reaches zero that it finds there in the value B When it does the
Hello World, this is where this cycle will end and then Empty the stack, notice that there it already
found the value zero
. the Red to finish the subroutine
return here and then to the hlt Yes to stop the execution basically This is what happens in
this program eh where precisely the different characters are passed to the output let's remember that
the characters were in this first part of the memory and then all the instructions that
are executed through these IP SP registers and the general use registers well this
was then eh a first approach to this character or simulator let's say 8 bit eh we will
continue in later videos I hope it helps you and See you next time Thank you very much for watching the
video
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