A slightly higher level assembly language for the Z80. This is meant to alleviate some of the pains of using assembly, but not going so high level as C for performance reasons. The plan is to use this to write an operating system.
Below is a simple example of Zircon code.
sub boot {
// Loading value by immediate
ld A, $FF
// By variable address
ld A, &my_var
// By variable
ld B, my_var
// Storing values by address
ld $6000*, A
// By constant
ld some_constant*, A
jp boot
fallthrough
}
Addresses (also known as "pointers") are specified by a * at the end of the number, to differentiate from an immediate. Other assembly languages use ld (some_constant), A or mov [some_constant], A.
A subroutine block requires that the programmer writes a jump (jmp or some conditional variant), ret, hlt or the special keyword fallthrough to ignore any safety checks and possibly run whatever lies past the block in memory.
- Be almost as low-level as normal assembly
- Make it faster and safer to write assembly
- Make it easier to organize assembly projects
- Provide good error handling
- Support multiple CPU targets (with different assembly instructions of course)
- Not be as high-level as C
- Not be a file format in itself. Which means the programmer has to for example, set memory addresses themselves
- Subroutine blocks
- Compile-time definitions
- Memory constants (in the ROM)
- Config things like for RAM areas
- Variables (in the RAM)
- Using blocks (temporary register aliases)
- If blocks
- Origin pragmas (for specifying addresses in the ROM)
- Multiple modules
- Complete instruction set
- Write-checker to require annotation of register modifications on subroutines
Thanks to Canop who wrote the char_reader crate that I used for my own version of CharReader