Add initial emulator implementation

This emulator provides a rough way for binaries designed for this CPU to be
executed in a virtual/emulated CPU for testing purposes. This patch also adds
a small test setup for automated assembly, execution and checking of register
postconditions for programs.

5 files changed, 88 insertions, 1 deletions

diff --git a/test/Makefile b/test/Makefile
index c2407c7..cb0f3ee 100644
--- a/test/Makefile
+++ b/test/Makefile
@@ -1,2 +1,3 @@
 test:
 	./full-pipeline/run-full-pipeline.sh
+	./emul/run-emul.sh
diff --git a/test/emul/002-nop.asm b/test/emul/002-nop.asm
new file mode 100644
index 0000000..31538ba
--- /dev/null
+++ b/test/emul/002-nop.asm
@@ -0,0 +1,7 @@
+; POST $1 = 0x0
+; POST $2 = 0x0
+; POST $3 = 0x0
+; POST $4 = 0x0
+; POST $5 = 0x0
+; POST $6 = 0x0
+nop
diff --git a/test/emul/003-small-loop.asm b/test/emul/003-small-loop.asm
new file mode 100644
index 0000000..ae2f81f
--- /dev/null
+++ b/test/emul/003-small-loop.asm
@@ -0,0 +1,10 @@
+; POST $1 = 0x2
+; POST $2 = 0x0
+; POST $3 = 0x28
+ldi $1, 2
+ldi $2, 20
+ldi $3, 0
+loop:
+	add $3, $3, $1
+	subi $2, $2, 1
+	bnz loop
diff --git a/test/emul/run-emul.sh b/test/emul/run-emul.sh
new file mode 100755
index 0000000..3b5ae69
--- /dev/null
+++ b/test/emul/run-emul.sh
@@ -0,0 +1,68 @@
+#!/bin/bash -e
+
+#
+# Script for running all of the automated tests that involve the assembler
+# and emulator.
+# These tests are assembly files with postconditions for registers specified
+# in special syntax within comments. They contain code to run, and the post-
+# conditions are checked in order to determine the test result.
+#
+
+fail() {
+	echo -e '[\e[1;31mFAIL\e[0m] '"$1:" "$2"
+}
+
+pass() {
+	echo -e '[\e[1;32mPASS\e[0m] '"$1"
+}
+
+clean() {
+	echo "Removing work dir $WORK"
+	rm -r "$WORK"
+}
+
+WORK=$(mktemp -d)
+pushd $(dirname "$0") >/dev/null
+export ASM="$PWD/../../assembler"
+export EMUL="$PWD/../../emulator"
+has_failure=0
+
+for asmfile in *.asm ; do
+	binfile="$WORK/$(sed -e 's/\.asm$/.bin/' <<< "$asmfile")"
+	outfile="$WORK/$(sed -e 's/\.asm$/.out/' <<< "$asmfile")"
+	# Assemble test code
+	if ! "$ASM" "$asmfile" "$binfile" ; then
+		fail "$asmfile" "test assembly failed"
+		continue
+	fi
+
+	"$EMUL" "$binfile" > "$outfile"
+
+	# Each postcondition line must hold true, and forms a separate test to
+	# help track down failures
+	(echo '; POST $0 = 0' ;
+	 echo '; POST $H = 0xFFFF' ;
+	 grep '^;\s\+POST\s\+' "$asmfile" ) | while read line ; do
+		reg=$(awk -F= '{print $1}' <<< "$line" | awk '{print $(NF)}')
+		val=$(awk -F= '{print $2}' <<< "$line"| awk '{print $1}')
+		subtest="${asmfile}:POST-${reg}"
+		# Scrape output of emulator for register value
+		actual=$(grep "$reg" "$outfile" | awk '{print $2}')
+		if [[ "$actual" -eq "$val" ]]; then
+			pass "$subtest"
+		else
+			fail "$subtest" "postcondition (expect $val, got $actual)"
+			has_failure=1
+		fi
+	done
+
+done
+popd >/dev/null
+
+if [[ "$failure" != "0" && "$NO_CLEAN" == "1"  ]] ; then
+	echo "Warning: Leaving work dir $WORK in place. Please remove this yourself"
+else
+	clean
+fi
+
+exit "$has_failure"
diff --git a/test/full-pipeline/005-small-loop.asm b/test/full-pipeline/005-small-loop.asm
index 3f2dc5f..5c47e51 100644
--- a/test/full-pipeline/005-small-loop.asm
+++ b/test/full-pipeline/005-small-loop.asm
@@ -1,6 +1,7 @@
 ldi $1, 2
-ldi $2, 100
+ldi $2, 20
 ldi $3, 0
 loop:
 	add $3, $3, $1
+	subi $2, $2, 1
 	bnz loop