asm-4: Rework of the 4th chapter #43

0xAX · 2025-04-12T13:24:50Z

Description

This PR provides rework of the 4th chapter.

Signed-off-by: Alexander Kuleshov <kuleshovmail@gmail.com>

klaudiagrz

First part of the review

klaudiagrz · 2025-04-19T11:31:49Z

content/asm_4.md


-Some time ago i started to write series of blog posts about assembly programming for x86_64. You can find it by asm tag. Unfortunately i was busy last time and there were not new post, so today I continue to write posts about assembly, and will try to do it every week.
+Building simple examples in the previous chapters, we have understood that a basic assembly program consists basically from two things:


Suggested change

Building simple examples in the previous chapters, we have understood that a basic assembly program consists basically from two things:

In the previous chapters, we built a few simple examples and figured out that a basic assembly program consists of just two main things:

klaudiagrz · 2025-04-19T11:32:17Z

content/asm_4.md


-## Reverse string
+We know that there many types of instructions:


Suggested change

We know that there many types of instructions:

We also learned that there are different types of instructions, like:

klaudiagrz · 2025-04-19T11:33:13Z

content/asm_4.md

+- Logical instructions
+- Control transfer instruction
+- String instructions
+- Other instructions like I/O instructions, flag control instructions, bits instructions.


Suggested change

- Other instructions like I/O instructions, flag control instructions, bits instructions.

- And others, like I/O, flag control, and bit manipulation instructions

klaudiagrz · 2025-04-19T11:35:10Z

content/asm_4.md


-First of all, I define initialized data. It will be placed in data section (You can read about sections in part):
+Some of them we have seen in the previous chapters already. In this chapter we will learn more details about them.


Suggested change

Some of them we have seen in the previous chapters already. In this chapter we will learn more details about them.

We’ve already seen some of them in action, but in this chapter, we’re going to dive a little deeper into how they work — especially when it comes to working with data.

klaudiagrz · 2025-04-21T07:25:54Z

content/asm_4.md

+
+## Data transfer instructions
+
+As you may guess based on the name, the data transfer instructions used to move data between memory and general-purpose registers. One of the most used and well know to us instruction is `mov`. We use it to move data between general-purpose registers, to move an immediate value to a general-purpose register, and to move data between memory and general purpose registers. The first two cases are simple. We just specify two general purpose registers which we want to use to move data. For example to copy value of the `rcx` register to `rax` we can with:


Suggested change

As you may guess based on the name, the data transfer instructions used to move data between memory and general-purpose registers. One of the most used and well know to us instruction is `mov`. We use it to move data between general-purpose registers, to move an immediate value to a general-purpose register, and to move data between memory and general purpose registers. The first two cases are simple. We just specify two general purpose registers which we want to use to move data. For example to copy value of the `rcx` register to `rax` we can with:

Data transfer instructions are used to move data between memory and general-purpose registers. One of the most commonly used and familiar instructions is `mov`. We use it to:

- Move data between general-purpose registers

- Move an immediate value to a general-purpose register

- Move data between memory and general-purpose registers

The first two cases are simple. We just specify two general-purpose registers we want to use to move data. For example, to copy the value of the `rcx` register into `rax`, we can use:

klaudiagrz · 2025-04-21T07:52:50Z

content/asm_4.md

-		inc rcx
-		;; loop again
-		jmp calculateStrLength
+;; Increment the value of the rcx


Suggested change

;; Increment the value of the rcx

;; Increment the value of the rcx register

klaudiagrz · 2025-04-21T07:53:01Z

content/asm_4.md

+;; Increment the value of the rcx
+inc rcx
+
+;; Add the value of the rcx to rdx


Suggested change

;; Add the value of the rcx to rdx

;; Add the value of rcx to rdx

Not sure: incremets/adds (as we are talking about "this instruction that DOES these actions"), or increment/add as just an action 🤔

I'd leave just an action

klaudiagrz · 2025-04-21T07:55:17Z

content/asm_4.md

+- `and` - Logical *and*. The instruction takes two operands and performs the logical *and* operation on them. The result is stored in the first operand.
+- `or` - Logical *or*. The instruction takes two operands and performs the logical *or* operation on them. The result is stored in the first operand.
+- `xor` - Logical *xor*. The instruction takes two operands and performs the logical *xor* operation on them. The result is stored in the first operand.
+- `not` - Logical *not*. The instruction takes two operands and performs the logical *not* operation on them. The result is stored in the first operand.


Suggested change

- `and` - Logical *and*. The instruction takes two operands and performs the logical *and* operation on them. The result is stored in the first operand.

- `or` - Logical *or*. The instruction takes two operands and performs the logical *or* operation on them. The result is stored in the first operand.

- `xor` - Logical *xor*. The instruction takes two operands and performs the logical *xor* operation on them. The result is stored in the first operand.

- `not` - Logical *not*. The instruction takes two operands and performs the logical *not* operation on them. The result is stored in the first operand.

- `and` - The instruction takes two operands and performs the logical *and* operation on them. The result is stored in the first operand.

- `or` - The instruction takes two operands and performs the logical *or* operation on them. The result is stored in the first operand.

- `xor` - The instruction takes two operands and performs the logical *xor* operation on them. The result is stored in the first operand.

- `not` - The instruction takes two operands and performs the logical *not* operation on them. The result is stored in the first operand.

I would remove first part of the explanation, as you anyway explain in the second sentence what logical operation is performed. Also, the name of the instruction itself is quite self-explanatory.

Also, consider to move the last sentence repeated in all instructions into a separate sentence underneath:

The result of these operations is always stored in the first operand.

Yes. This is very good suggestion.

klaudiagrz · 2025-04-21T07:57:34Z

content/asm_4.md

-exitFromRoutine:
-		;; return to _start
-		ret
+;; If rax = 1 and rbx = 0, rax will store 0


Suggested change

;; If rax = 1 and rbx = 0, rax will store 0

;; If rax = 1 and rbx = 0, rax stores 0

klaudiagrz · 2025-04-21T07:57:43Z

content/asm_4.md

+;; If rax = 1 and rbx = 0, rax will store 0
+and rax, rbx
+
+;; If rax = 1 and rbx = 0, rax will store 1


Suggested change

;; If rax = 1 and rbx = 0, rax will store 1

;; If rax = 1 and rbx = 0, rax stores 1

Signed-off-by: Alexander Kuleshov <kuleshovmail@gmail.com>

asm-4: Rework of the 4th chapter

f42b875

Signed-off-by: Alexander Kuleshov <kuleshovmail@gmail.com>

0xAX requested a review from klaudiagrz as a code owner April 12, 2025 13:24

asm-4: add more links from GNU to exclusion from link checker

23d97e6

Signed-off-by: Alexander Kuleshov <kuleshovmail@gmail.com>

klaudiagrz reviewed Apr 21, 2025

View reviewed changes

asm-4: Fixes for editoral changes

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Signed-off-by: Alexander Kuleshov <kuleshovmail@gmail.com>

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asm-4: Rework of the 4th chapter #43

asm-4: Rework of the 4th chapter #43

0xAX commented Apr 12, 2025

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		Some time ago i started to write series of blog posts about assembly programming for x86_64. You can find it by asm tag. Unfortunately i was busy last time and there were not new post, so today I continue to write posts about assembly, and will try to do it every week.
		Building simple examples in the previous chapters, we have understood that a basic assembly program consists basically from two things:

	Building simple examples in the previous chapters, we have understood that a basic assembly program consists basically from two things:
	In the previous chapters, we built a few simple examples and figured out that a basic assembly program consists of just two main things:


		## Reverse string
		We know that there many types of instructions:

	We know that there many types of instructions:
	We also learned that there are different types of instructions, like:

	- Other instructions like I/O instructions, flag control instructions, bits instructions.
	- And others, like I/O, flag control, and bit manipulation instructions


		First of all, I define initialized data. It will be placed in data section (You can read about sections in part):
		Some of them we have seen in the previous chapters already. In this chapter we will learn more details about them.

	Some of them we have seen in the previous chapters already. In this chapter we will learn more details about them.
	We’ve already seen some of them in action, but in this chapter, we’re going to dive a little deeper into how they work — especially when it comes to working with data.


		## Data transfer instructions

		As you may guess based on the name, the data transfer instructions used to move data between memory and general-purpose registers. One of the most used and well know to us instruction is `mov`. We use it to move data between general-purpose registers, to move an immediate value to a general-purpose register, and to move data between memory and general purpose registers. The first two cases are simple. We just specify two general purpose registers which we want to use to move data. For example to copy value of the `rcx` register to `rax` we can with:

-As you may guess based on the name, the data transfer instructions used to move data between memory and general-purpose registers. One of the most used and well know to us instruction is `mov`. We use it to move data between general-purpose registers, to move an immediate value to a general-purpose register, and to move data between memory and general purpose registers. The first two cases are simple. We just specify two general purpose registers which we want to use to move data. For example to copy value of the `rcx` register to `rax` we can with:
+Data transfer instructions are used to move data between memory and general-purpose registers. One of the most commonly used and familiar instructions is `mov`. We use it to:
+- Move data between general-purpose registers
+- Move an immediate value to a general-purpose register
+- Move data between memory and general-purpose registers
+The first two cases are simple. We just specify two general-purpose registers we want to use to move data. For example, to copy the value of the `rcx` register into `rax`, we can use:

	;; Increment the value of the rcx
	;; Increment the value of the rcx register

	;; Add the value of the rcx to rdx
	;; Add the value of rcx to rdx

	;; If rax = 1 and rbx = 0, rax will store 0
	;; If rax = 1 and rbx = 0, rax stores 0

	;; If rax = 1 and rbx = 0, rax will store 1
	;; If rax = 1 and rbx = 0, rax stores 1

asm-4: Rework of the 4th chapter #43

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asm-4: Rework of the 4th chapter #43

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