Original subtitles

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- [Instructor] We've looked at the MASM32 assembler

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but we'll be using the GoAsm64 assembler from here on in.

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The assembler instructions are the same

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and the syntax is largely similar.

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With the coding examples now,

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we'll start to build up

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our file encryptor demonstration program.

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I've got a new GoAsm64 classic console project opened

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called an enigmatic.

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I'll make a couple of changes to

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the skeleton Easy Code provides.

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I'll change the constant null to zero

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and check change the code to call, GetModuleHandleA.

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At the machine level,

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our smallest data type is a byte

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which we define with the declaration DB.

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So in the data section we can, write, for example

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slot1 db, and we'll set it to the value five,

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slot2 db, we'll set that to the value two,

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slot3 db, and we'll set that to the value three.

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Sometimes it's useful to declare a number of variables

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each with the same value.

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We can do this with the juke keyword.

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For example, making a three byte array,

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each with the value one

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we can say settings db three bytes

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with a duplicated value of one.

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We've used standard decimal values to

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initialize these variables

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but sometimes we want to use a hexadecimal value.

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You can optionally proceed a hexadecimal value with a zero

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but it's necessary to add a suffix of h.

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For example, plug1 db 2Fh,

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plug2 db 16h.

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In MASM, we have a dot data question mark section.

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However, in GoAsm, if we don't want to initialize

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the variable we just declare it with a question mark.

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Rotten db question mark.

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The assembler doesn't have a string data type

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but as we've seen it does recognize a string

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as a sequence of bytes

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so we can use the welcome db Enigma style file encryptor.

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And this declares an array of bytes, which has length 27.

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We can also combine data declarations on a line,

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so we'll add a carriage return

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and line feed to the welcome line with 0Dh, 0Ah.

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We can declare a double bytes,

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a word in assembler terminology with a DW declaration

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and a 32 bit value with a double word DD declaration.

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We declare a full 64 bit value as DQ.

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Let's declare five quad-word rotor variables

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and initialize them with hexadecimal values.

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Okay, I'll save this now.

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Well, we won't be using them in this course.

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GoAsm also allows us to declare a variable

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of 10 bytes using the mnemonic DT.