1 files changed, 32 insertions, 20 deletions

diff --git a/src/user/knob/format.c b/src/user/knob/format.c
index c5d2447..cdc1687 100644
--- a/src/user/knob/format.c
+++ b/src/user/knob/format.c
@@ -42,8 +42,8 @@ struct format_spec {
     CHAR,
     STRING,
     UNSIGNED_DECIMAL,
-    HEXADECIMAL
-    //TODO: signed decimal
+    HEXADECIMAL,
+    SIGNED_DECIMAL
   } kind;
 };
 
@@ -73,6 +73,9 @@ static const char *get_format(const char *from, struct format_spec *format_out)
   case 'x':
     format_out->kind = HEXADECIMAL;
     break;
+  case 'd':
+    format_out->kind = SIGNED_DECIMAL;
+    break;
   default:
     format_out->kind = UNKNOWN;
     break;
@@ -81,7 +84,17 @@ static const char *get_format(const char *from, struct format_spec *format_out)
   return from + 1;
 }
 
-//char debug[] = "-- format_v: fmt = \"   \"...";
+static uint8_t get_digits(uint32_t k) {
+  if (k >= 1000000000)
+    return 10;
+  uint8_t r = 1;
+  uint32_t n = 10;
+  while (k >= n) {
+    ++r;
+    n *= 10;
+  }
+  return r;
+}
 
 //allocates new memory
 char *format_v(const char *fmt, va_list args) {
@@ -92,11 +105,6 @@ char *format_v(const char *fmt, va_list args) {
   buf_i = buf;
 
   while (*fmt) {
-  //debug[20] = *fmt;
-  //debug[21] = fmt[1];
-  //debug[22] = fmt[2];
-  //_system_log(debug);
-
     if (*fmt != '%') {
       ensure(1);
       *(buf_i++) = *(fmt++);
@@ -137,20 +145,24 @@ char *format_v(const char *fmt, va_list args) {
         continue;
 
         uint32_t k;
-      case UNSIGNED_DECIMAL:
+      case SIGNED_DECIMAL:
         k = va_arg(args, uint32_t);
-        if (!form.len) {
-          if (k >= 1000000000)
-            form.len = 10;
-          else {
-            uint32_t n = 10;
-            ++form.len;
-            while (k >= n) {
-              ++form.len;
-              n *= 10;
-            }
-          }
+        bool is_neg = k & 0x80000000;
+        if (is_neg) {
+          ensure(1);
+          *(buf_i++) = '-';
+          k = -k;
         }
+        if (!form.len)
+          form.len = get_digits(k);
+        else if (is_neg)
+          --form.len;
+        goto print_dec;
+      case UNSIGNED_DECIMAL:
+        k = va_arg(args, uint32_t);
+        if (!form.len)
+          form.len = get_digits(k);
+      print_dec:
         ensure(form.len);
         const uint32_t len_backup = form.len;
         while (form.len--) {