add tests and update documentation

README.md

@@ -65,7 +65,7 @@ Additionally, trailing `.`s on the end of the last line may be omitted.
 
 Trilangle ditches the hexagonal memory layout in favor of a stack. Technically, it's not a pure stack as it is possible to index into it, but the majority of operations treat it as such.
 
-Each item on the stack is a 24-bit signed integer.
+Each item on the stack is a 24-bit integer. Different instructions variously treat it as signed or unsigned.
 
 ## Instructions
 
@@ -180,6 +180,8 @@ When `{` is approached from the northeast or southeast, that interpreter thread
 | b | e | b |
 | a | d | a |
 
+If the value on top of a stack is negative, that entire stack is carried over.
+
 ## Interpreter flags
 
 When run with the `-d` flag, the interpreter enters "debug mode." Before executing each instruction, it prints the location of the IP and the opcode that it is pointing at, and it waits for you to press enter before continuing. If the `-s` flag is also set, the interpreter will print the stack contents as well as the IP.

src/thread.cpp

@@ -404,15 +404,15 @@ void thread::tick() {
                 break;
             }
 
-            int24_t top = m_stack.back();
+            size_t index = static_cast<size_t>(m_stack.back()) & 0x00ff'ffffU;
             m_stack.pop_back();
 
-            if (m_flags.warnings && (top < INT24_C(0) || m_stack.size() < static_cast<size_t>(top) + 1)) UNLIKELY {
+            if (m_flags.warnings && m_stack.size() < index + 1) UNLIKELY {
                 cerr << "Warning: Attempt to index out of stack bounds (size = " << m_stack.size()
-                     << ", index = " << top << ")\n";
+                     << ", index = " << index << ")\n";
             }
 
-            size_t i = m_stack.size() - static_cast<size_t>(top) - 1;
+            size_t i = m_stack.size() - index - 1;
             m_stack.push_back(m_stack[i]);
 
             break;

tests/cli/arithmetic/add.trg

@@ -0,0 +1,3 @@
+  ?
+ ? p
++ @ .

tests/cli/arithmetic/index.sh

@@ -0,0 +1,15 @@
+#!/bin/bash
+
+set -eu
+
+folder=$(dirname "$0")
+
+five=$($TRILANGLE "${folder}/add.trg" <<<'3 2')
+one=$($TRILANGLE "${folder}/sub.trg" <<<'3 2')
+minustwo=$($TRILANGLE "${folder}/sdiv.trg" <<<'-5 2')
+twopowtwentytwo=$($TRILANGLE "${folder}/udiv.trg" <<<"$((0x800000)) 2")
+
+test 5 = "$five"
+test 1 = "$one"
+test -2 = "$minustwo"
+test $((0x400000)) = "$twopowtwentytwo"

tests/cli/arithmetic/sdiv.trg

@@ -0,0 +1,3 @@
+  ?
+ ? !
+: @ .

tests/cli/arithmetic/sub.trg

@@ -0,0 +1,3 @@
+  ?
+ ? !
+- @ .

tests/cli/arithmetic/udiv.trg

@@ -0,0 +1,3 @@
+  ?
+ ? p
+d @ .

tests/cli/cat/index.sh

@@ -13,3 +13,6 @@ folder=$(dirname "$0")
 output=$($TRILANGLE "${folder}/cat.trg" <<<"$text")
 # Okay so on Windows the newline characters are different. Isn't this fun?
 test "$text" = "${output//$'\r'/}"
+
+x=$((0x912345))
+test $x = "$($TRILANGLE "${folder}/uint.trg" <<<$x)"

tests/cli/cat/uint.trg

@@ -0,0 +1,2 @@
+ ?
+p @

tests/cli/print1/index.sh

@@ -6,3 +6,4 @@ folder=$(dirname "$0")
 
 test 1 = "$($TRILANGLE "${folder}/int.trg")"
 test 1 = "$($TRILANGLE -a "${folder}/char.trg")"
+test 1 = "$($TRILANGLE "${folder}/uint.trg")"

tests/cli/print1/uint.trg

@@ -0,0 +1,3 @@
+  '
+ 1 @
+p . .

tests/compiler/arithmetic

@@ -0,0 +1 @@
+../cli/arithmetic/