user_visible_state: Decode MSw

1 files changed, 26 insertions, 2 deletions

diff --git a/user_visible_state.c b/user_visible_state.c
index 4616ca4..f171ab5 100644
--- a/user_visible_state.c
+++ b/user_visible_state.c
@@ -43,9 +43,33 @@ static void show_tr(void)
 
 static void show_msw(void)
 {
-	unsigned short msw;
+	static const struct msw_bit {
+		int pos;
+		const char *str;
+	} bits[] = {
+		{0, "PE"},
+		{1, "MP"},
+		{2, "EM"},
+		{3, "TS"},	/* this is actually interesting */
+		{4, "ET"},
+		{5, "NE"},
+	};
+
+	unsigned short msw, remaining;
 	asm ("smsww %0" : "=rm" (msw));
-	printf("MSW:    0x%04X\n", msw);
+	printf("MSW:    0x%04X", msw);
+
+	remaining = msw;
+	for (int i = 0; i < sizeof(bits) / sizeof(bits[0]); i++) {
+		if (msw & (1 << bits[i].pos)) {
+			printf(" %s", bits[i].str);
+			remaining &= ~(1 << bits[i].pos);
+		}
+	}
+	if (remaining)
+		printf(" unknown:0x%x", remaining);
+
+	printf("\n");
 }
 
 static void show_flags(void)