From b328a92f0e3c648bad7ef47a98f1db75e545789a Mon Sep 17 00:00:00 2001
From: Paul Duncan <pabs@pablotron.org>
Date: Wed, 24 Jul 2024 22:39:59 -0400
Subject: initial commit

---
 hi.s | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)
 create mode 100644 hi.s

(limited to 'hi.s')

diff --git a/hi.s b/hi.s
new file mode 100644
index 0000000..90190cb
--- /dev/null
+++ b/hi.s
@@ -0,0 +1,31 @@
+// hi.s: print "alonzo sucks!" to standard output and then exit.
+//
+// uses write() and exit() linux system calls directly to elide libc and
+// assembles to a static, 384 byte arm64 binary.
+
+// entry point
+//
+// uses 32-bit registers (wN) instead of 64-bit registers (xN) to
+// save a few bytes in the assembled binary
+.text
+.global _start
+_start:
+  // write(stdout, msg, len)
+  mov w0, #1    // stdout fd (1)
+  ldr w1, =msg  // message
+  mov w2, len   // message length
+  mov w8, #64   // write() (64)
+  svc #0        // call write()
+
+  // exit(0)
+  mov w0, #0    // exit code (0)
+  mov w8, #93   // exit() (93)
+  svc #0        // call exit()
+
+// message and message length
+//
+// technically the message belongs in the .rodata section, but sticking
+// it here allows it to be packed after _start and the saves ~60 bytes
+// in the assembled binary
+msg: .ascii "alonzo sucks!\n" // message (14 bytes)
+len = . - msg // message length
-- 
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