belivenn / hello-solana-asm

Hello, World! - written in sBPF (Solana eBPF) assembly.

Hello, Solana!

A simple SBF (Solana eBPF) Assembly program that prints "Hello, Solana!" using sol_log. Includes fully-annotated code below, along with a Makefile, linker file, build, deploy and test scripts.

.globl e                     ; e - "entrypoint" but 9 bytes cheaper!
e:
    lddw r1, message         ; load address of "message" into r1
    lddw r2, 14              ; load "14" (our string length) into r2
    call sol_log_            ; call sol_log_ - this reads from r1 and r2
    # r0 = 0                 ; r0 is already 0 (SUCCESS). Let's save 1 CU.
    exit
.extern sol_log_             ; declare external symbol "sol_log_"
.section .rodata             ; read-only data section
message:
    .ascii "Hello, Solana!"  ; define "message" as used above

The program and its linker file have been reasonably well-optimized to remove junk we don't need, leading to a compiled program size of just 1,168 bytes, and consuming just 104 CUs.