Can you comment these codes please?

INCLUDE asmlib.inc

CreateFileA Proto,

fileName: PTR BYTE,

accessMode: DWORD,

shareMode : DWORD,

securityAttrib : DWORD,

creationDispo : DWORD,

flagsAndAttrib : DWORD,

hTemplateFile : DWORD

ReadFile PROTO,

hHandle : DWORD,

lpBuffer : PTR BYTE,

nNumberOfBytesToRead : DWORD,

pNumberOfBytesRead : PTR DWORD,

lpOverlapped : PTR DWORD

CloseHandle PROTO, hObject : DWORD

WriteFile PROTO,

hHandle : DWORD,

lpBuffer : PTR BYTE,

nNumberOfBytesToWrite : DWORD,

pNumberOfBytesWritten : PTR DWORD,

lpOverlapped : PTR DWORD

GetLastError PROTO ; get most recent error return value

fWriteChar PROTO

fReadChar PROTO

GENERIC$\_$READ $=80000000$h

GENERIC$\_$WRITE $=40000000$h

GENERIC$\_$EXECUTE $=20000000$h

GENERIC$\_$ALL $=10000000$h

CREATE$\_$NEW $=1$

CREATE$\_$ALWAYS $=2$

OPEN$\_$EXISTING $=3$

OPEN$\_$ALWAYS $=4$

TRUNCATE$\_$EXISTING $=5$

FILE$\_$ATTRIBUTE$\_$NORMAL $=80$h

NULL $=0$

$.$data

fname BYTE "test.txt$",0$

buffer BYTE $0$

$.$code

main PROC

; Test fWriteChar

mov edx, OFFSET fname ; File name

mov eax, $0$

call readChar

INVOKE fWriteChar

INVOKE fReadChar

exit

main ENDP

fWriteChar PROC uses edx eax

local outChar : BYTE, bytesWritten : DWORD, fHandle : DWORD

mov outChar, al ; Store the character to be written in the local variable

mov eax, $0$ ; Move the file name to eax register

; Open the file for writing

INVOKE CreateFileA, edx, GENERIC$\_$WRITE, NULL, NULL, OPEN$\_$ALWAYS, FILE$\_$ATTRIBUTE$\_$NORMAL, NULL

mov fHandle, eax ; Store the file handle

; Write the character to the file

INVOKE WriteFile, fHandle, ADDR outChar, $1,$ ADDR bytesWritten, NULL

; Close the file

INVOKE CloseHandle, fHandle

ret

fWriteChar ENDP

fReadChar PROC uses edx eax

local inChar: BYTE, bytesRead: DWORD, fHandle: DWORD

mov eax, $0$ ; Move the file name to eax register

; Open the file for reading

INVOKE CreateFileA, edx, GENERIC$\_$READ, NULL, NULL, OPEN$\_$EXISTING, FILE$\_$ATTRIBUTE$\_$NORMAL, NULL

mov fHandle, eax ; Store the file handle

mov eax, $0$

; Read a single character from the file

INVOKE ReadFile, fHandle, ADDR buffer, $1,$ ADDR bytesRead, NULL

mov edx, OFFSET buffer

call writeLine

; Close the file

INVOKE CloseHandle, fHandle

mov al$,$ inChar ; Move the read character to al register for return

ret

fReadChar ENDP

END main