Moving a BYTE to a BYTE

Question

I am in a Machine Architecture and Assembly Language class, and I am supposed to create a MASM program that creates the Fibonacci sequence up to a user defined number, that is inclusively between 1 and 46. When I try to transfer the string stored in a BYTE labeled buffer, which is where the book authors ReadString procedure stores a string, to another BYTE labeled user, I receive this build output:

1>------ Build started: Project: MASM2, Configuration: Debug Win32 ------
1>  Assembling fibonacci.asm...
1>fibonacci.asm(39): error A2070: invalid instruction operands
1>C:\Program Files (x86)\MSBuild\Microsoft.Cpp\v4.0\V140\BuildCustomizations\masm.targets(50,5): error MSB3721: The command "ml.exe /c /nologo /Sg /Zi /Fo"Debug\fibonacci.obj" /Fl"MASM2.lst" /I "c:\Irvine" /W3 /errorReport:prompt  /Tafibonacci.asm" exited with code 1.
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

I am not sure why I can't move to same sized objects into each other. I commented out the user parts and printed the buffer, and it is storing the input as a string correctly. Any help is greatly appreciated.

***Note: We are using the book Assembly Language for the x86 Processor, 7th Ed. by Kip Irvine, and using his Irvine32 Library.

; Calculate Fibonacci to the nth degree

INCLUDE Irvine32.inc

.data
buffer BYTE 21 DUP(0)
welcome BYTE "Welcome to Fibonacci! My name is Zach, I will be your programmer today!", 0
question BYTE "What is your name?: ", 0
greet BYTE "Hello, ", 0

user BYTE ?

prompt BYTE "Enter a number from 1 to 46: ", 0
debrief BYTE "GoodBye"

input SDWORD ?

fib DWORD ?

.code
main proc

     call Clrscr

     ;Print Welcome Screen
     mov edx,OFFSET welcome
     call WriteString
     call Crlf


     ;Get Username and Greet
     mov edx,OFFSET question
     call WriteString
     call Crlf

     mov edx,OFFSET buffer
     mov ecx,SIZEOF buffer
     call ReadString
     mov user, buffer

     mov edx,OFFSET greet
     call WriteString
     mov edx,OFFSET buffer
     call WriteString
     call Crlf


    ;Get Input-- 1 to 46

     mov edx,OFFSET prompt
     call WriteString

     call ReadInt
     mov input,eax


     ;Validate n

     ;Calculate-5 terms per line w/5 spaces between
     mov ecx,input
     mov al, ','
     mov eax,1
     call WriteDec

     start:
     call WriteChar
     call WriteDec
     mov fib, eax
     add eax,fib
     LOOP start

     ;Debrief
     call Crlf
     mov edx,OFFSET debrief
     call WriteString
    invoke ExitProcess,0
main endp
end main

Fun New Output:

1>------ Build started: Project: MASM2, Configuration: Debug Win32 ------
1>  Assembling fibonacci.asm...
1>fibonacci.asm(44): error A2022: instruction operands must be the same size
1>fibonacci.asm(45): error A2022: instruction operands must be the same size
1>C:\Program Files (x86)\MSBuild\Microsoft.Cpp\v4.0\V140\BuildCustomizations\masm.targets(50,5): error MSB3721: The command "ml.exe /c /nologo /Sg /Zi /Fo"Debug\fibonacci.obj" /Fl"MASM2.lst" /I "c:\Irvine" /W3 /errorReport:prompt  /Tafibonacci.asm" exited with code 1.
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

Answer 1

I changed the code so ReadString goes straight to User, and the output is correct.

 ;Get Username and Greet
 mov edx,OFFSET question
 call WriteString
 call Crlf

 mov edx,OFFSET user
 mov ecx,SIZEOF user
 call ReadString

 mov edx,OFFSET greet
 call WriteString
 mov edx,OFFSET user
 call WriteString
 call Crlf