5872

README.md

@@ -329,13 +329,13 @@ transparently copy it to the `data` segment and replace it with its address.
 Strings are the only place where a SubX word is allowed to contain spaces.
 
 That should be enough information for writing SubX programs. The `apps/`
-directory provides some fodder for practice in the `apps/ex*` files, giving a
+directory provides some fodder for practice in the `apps/ex*.subx` files,
-more gradual introduction to SubX features. This repo includes binaries for
+giving a more gradual introduction to SubX features. This repo includes
-all examples. At any commit, an example's binary should be identical bit for
+binaries for all examples. At any commit, an example's binary should be
-bit with the result of translating the corresponding `.subx` file. The binary
+identical bit for bit with the result of translating the corresponding `.subx`
-should also be natively runnable on a Linux system running on Intel x86
+file. The binary should also be natively runnable on a Linux system running on
-processors, either 32- or 64-bit. If either of these invariants is broken it's
+Intel x86 processors, either 32- or 64-bit. If either of these invariants is
-a bug on my part.
+broken it's a bug on my part.
 
 ## Running
 

apps/ex1.mu

@@ -0,0 +1,13 @@
+# First example: return the answer to the Ultimate Question of Life, the
+# Universe, and Everything.
+#
+# To run:
+#   $ ./translate_mu apps/ex1.mu
+#   $ ./a.elf
+# Expected result:
+#   $ echo $?
+#   42
+
+fn main -> result/ebx: int {
+  result <- copy 0x2a  # Mu requires hexadecimal
+}

apps/ex1.subx

@@ -12,7 +12,7 @@
 
 Entry:
 # exit(42)
-bb/copy-to-ebx  2a/imm32  # 42 in hex
+bb/copy-to-ebx  0x2a/imm32  # 42 in hex
 e8/call  syscall_exit/disp32
 
 # . . vim:nowrap:textwidth=0