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douggilliland / R32V2020

My 32-bit RISC CPU for smallish FPGAs
GNU General Public License v3.0
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Data Representation in the assembler #38

Closed douggilliland closed 5 years ago

douggilliland commented 5 years ago

@mjgpy3 I can't remember what the data representation is in the assembler.

Can you write a short section in the Assembler Wiki? Maybe in this section that I started. https://github.com/douggilliland/R32V2020/wiki/Assembler#Data_File_Format

I think we had

label: .string "This is a string" label2: .long 0x12345678

Is that the format?

This will need some work for the opcodes to pick up the label. Maybe we need something like:

lil r8,label.LOWER liu r8, label.UPPER

The label is at a 32-bit address and the only way we have to get the address is in two parts.

What do you think?

douggilliland commented 5 years ago

@mjgpy3 I figured out part of it and updated the Assembler wiki. The _dat file needs to be in the .HEX format just like the _ins file. It gets loaded the same.

There's some wrong stuff in there too. See the C021 example I checked in.

https://github.com/douggilliland/R32V2020/tree/master/VHDL/Programs/C021-Data_RAM_Init_Vals

douggilliland commented 5 years ago

@mjgpy3

Here is what .string 'Hello, World' looks like (manually created):

:0400000048656C6C77 :040001006F2C2057E9 :040002006F726C6449 :0400030000000000F9 :00000001FF

C029... code