From 4eea879cdb354382fa577719ecb93ac25570560b Mon Sep 17 00:00:00 2001
From: sejo <tejocote+codeberg@posteo.net>
Date: Wed, 7 Jul 2021 16:08:55 -0500
Subject: [PATCH] little person computer program

---
 src/little_person_computer.gmo | 62 ++++++++++++++++++++++++++++++++++
 1 file changed, 62 insertions(+)

diff --git a/src/little_person_computer.gmo b/src/little_person_computer.gmo
index fdc3c6a..5dcbef7 100644
--- a/src/little_person_computer.gmo
+++ b/src/little_person_computer.gmo
@@ -8,6 +8,68 @@ is uses the decimal system, with words of three-digits each.
 
 it has ten instructions and 100 memory addresses.
 
+# example programs
+
+written in the corresponding assembly language.
+
+as part of the {s-camino} practice.
+
+## multiplication of two numbers
+
+### no labels
+
+pure assembler version, no labels.
+
+* 15 is the address for the result
+* 16 is the address for 'a'
+* 17 is the addres for 'b'
+
+```
+        INP
+        STA 16
+        INP
+        STA 17
+        BRZ 11
+        LDA 16
+        ADD 15
+        STA 15
+        LDA 17
+        SUB 14
+        BRA 3
+        LDA 15
+        OUT
+        HLT
+        DAT 1
+        DAT 0
+        DAT 0
+        DAT 0
+```
+
+### with labels
+
+the same behavior as above, but using labels for easier programming and reading
+
+```
+inputs  INP
+        STA a
+        INP
+loop    STA b
+        BRZ print // finish if b is 0
+        LDA a
+        ADD result
+        STA result
+        LDA b
+        SUB one
+        BRA loop
+print   LDA result
+        OUT
+        HLT
+one     DAT 1
+result  DAT 0
+a       DAT 0
+b       DAT 0
+```
+
 # external links
 
 => https://teachcomputerscience.com/little-man-computer/ little man computer