diff --git a/src/asm/output.cpp b/src/asm/output.cpp
index 70a251c2..d92e6ef7 100644
--- a/src/asm/output.cpp
+++ b/src/asm/output.cpp
@@ -490,12 +490,14 @@ static bool dumpMacros(FILE *file) {
 }
 
 void out_WriteState(std::string name, std::vector<StateFeature> const &features) {
+	// State files may include macro bodies, which may contain arbitrary characters,
+	// so output as binary to preserve them.
 	FILE *file;
 	if (name != "-") {
-		file = fopen(name.c_str(), "w");
+		file = fopen(name.c_str(), "wb");
 	} else {
 		name = "<stdout>";
-		file = fdopen(STDOUT_FILENO, "w");
+		file = fdopen(STDOUT_FILENO, "wb");
 	}
 	if (!file)
 		err("Failed to open state file '%s'", name.c_str());
diff --git a/test/asm/state-file/a.asm b/test/asm/state-file/a.asm
new file mode 100644
index 00000000..b8e47b31
--- /dev/null
+++ b/test/asm/state-file/a.asm
@@ -0,0 +1,26 @@
+OPT Wno-unmapped-char
+
+DEF constant EQU 1
+DEF variable = 2
+DEF string EQUS "hello!"
+CHARMAP "c", 4
+MACRO polo
+	db 5
+ENDM
+
+def variable += 1
+
+def con2 equ -1
+def var2 = variable**2
+def str2 equs strcat("{string}", "\0\n\t\r")
+charmap "c2", 10, -11, 987654321
+
+PURGE polo
+MACRO mac2
+	!?@#;^&
+ENDM
+
+newcharmap map2, main
+charmap "\0\n\t\r", "\t", "\r", "\0", "\n"
+
+REDEF string EQUS "goodbye~"
diff --git a/test/asm/state-file/a.dump.asm b/test/asm/state-file/a.dump.asm
new file mode 100644
index 00000000..d3205863
--- /dev/null
+++ b/test/asm/state-file/a.dump.asm
@@ -0,0 +1,27 @@
+; File generated by rgbasm
+
+; Numeric constants
+def constant equ $1
+def con2 equ $ffffffff
+
+; Variables
+def variable = $3
+def var2 = $9
+
+; String constants
+def string equs "goodbye~"
+def str2 equs "hello!\0\n\t\r"
+
+; Character maps
+newcharmap main
+charmap "c", $4
+charmap "c2", $a, $fffffff5, $3ade68b1
+newcharmap map2
+charmap "c", $4
+charmap "c2", $a, $fffffff5, $3ade68b1
+charmap "\0\n\t\r", $9, $d, $0, $a
+
+; Macros
+macro mac2
+	!?@#;^&
+endm
diff --git a/test/asm/test.sh b/test/asm/test.sh
index c12246d4..5bf64923 100755
--- a/test/asm/test.sh
+++ b/test/asm/test.sh
@@ -129,6 +129,40 @@ for i in *.asm; do
 	done
 done
 
+# These tests do their own thing
+
+i="state-file"
+if which cygpath &>/dev/null; then
+	# MinGW translates path names before passing them as command-line arguments,
+	# but does not do so when they are prefixed, so we have to do it ourselves.
+	RGBASMFLAGS="-Weverything -s all:$(cygpath -w "$o")"
+else
+	RGBASMFLAGS="-Weverything -s all:$o"
+fi
+for variant in '' '.pipe'; do
+	(( tests++ ))
+	echo "${bold}${green}${i%.asm}${variant}...${rescolors}${resbold}"
+	if [ -z "$variant" ]; then
+		"$RGBASM" $RGBASMFLAGS "$i"/a.asm >"$output" 2>"$errput"
+	else
+		# shellcheck disable=SC2002
+		cat "$i"/a.asm | "$RGBASM" $RGBASMFLAGS - >"$output" 2>"$errput"
+	fi
+
+	tryDiff /dev/null "$output" out
+	our_rc=$?
+	tryDiff /dev/null "$errput" err
+	(( our_rc = our_rc || $? ))
+	tryDiff "$i"/a.dump.asm "$o" err
+	(( our_rc = our_rc || $? ))
+
+	(( rc = rc || our_rc ))
+	if [[ $our_rc -ne 0 ]]; then
+		(( failed++ ))
+		break
+	fi
+done
+
 if [[ "$failed" -eq 0 ]]; then
 	echo "${bold}${green}All ${tests} tests passed!${rescolors}${resbold}"
 else