Assembler

Assembler create a real code from mnemonic representation of code

Stack VM has a very complete assembler with a lot of directives (see DIRECTIVES table).
Instructions can be extended easily on vm_opcodes_def.c.
For that you can edit one of the not use instructions (Usually after the HALT instruction).
Up to 8 arguments can be specified. The assembler stop to search after the first ARG_NON in the list.
When read the program it’s ensure that the data type is correct and emit the code into the program.
The possible arguments types are:

  • ARG_NON: Non arguments. All arguments defined after this are ignored.

  • ARG_U08: Unsigned 8 bits number.

  • ARG_U16: Unsigned 16 bits number.

  • ARG_U32: Unsigned 32 bits number.

  • ARG_I08: Signed 8 bits number.

  • ARG_I16: Signed 16 bits number.

  • ARG_I32: Signed 32 bits number.

  • ARG_F32: Float 32 bits number.

  • ARG_STR: String.

  • ARG_NVL: Have n values from previous argument, next argument is type. This type is not actually supported by the VM but exist for future expansions.


In program all numbers can be expressed as decimal or hexadecimal

Directives

Directive

Description

.equ

Assigns a value to a label.

.macro

Start of a macro. Takes the name as parameter.

.endm

End of a macro definition.

.include

Start reading from a specified file.

.label

Assign the address at this point to label.

.comment

Comment line.

.datau8

Insert a list of unsigned 8 bits values.

.datau16

Insert a list of unsigned 16 bits values.

.datau32

Insert a list of unsigned 32 bits values.

.datai8

Insert a list of signed 8 bits values.

.datai16

Insert a list of signed 16 bits values.

.datai32

Insert a list of signed 32 bits values.

.dataf32

Insert a list of float 32 bits values.

.string

Insert string text.

NOTE 1: All content after ; is considered comment.

NOTE 2: Value $HERE represent actual address pointer, can be offsetted ex: .equ label $HERE + 3

NOTE 3: Labels can be offsetted when referenced ex: GOTO label + 5