diff --git a/src/Tokenizer.zig b/src/Tokenizer.zig
index e20f76d9..0cf0c9fa 100644
--- a/src/Tokenizer.zig
+++ b/src/Tokenizer.zig
@@ -1698,14 +1698,17 @@ pub fn next(self: *Tokenizer) Token {
                 },
             },
             .pp_num_exponent => switch (c) {
-                'a'...'z',
-                'A'...'Z',
+                'a'...'o',
+                'q'...'z',
+                'A'...'O',
+                'Q'...'Z',
                 '0'...'9',
                 '_',
                 '.',
                 '+',
                 '-',
                 => state = .pp_num,
+                'p', 'P' => {},
                 else => {
                     id = .pp_num;
                     break;
diff --git a/test/cases/numbers.c b/test/cases/numbers.c
index af67fe24..8962a006 100644
--- a/test/cases/numbers.c
+++ b/test/cases/numbers.c
@@ -14,6 +14,12 @@ float m = 12E-2f;
 float n = 0x12P+2;
 float o = 0x12p-2;
 _Static_assert(0xE+0xC == 0xE + 0xC, "");
+double p = 0x1.ep-1;
+double q = 0x1.eP-1;
+double r = 0x1.Ep-1;
+double s = 0x1.EP-1;
+double t = 1.ep-1;
+double u = 1.pp-1;
 
 #define EXPECTED_ERRORS "numbers.c:1:9: error: invalid suffix 'b' on integer constant" \
     "numbers.c:2:9: error: invalid suffix 'x' on integer constant" \
@@ -25,4 +31,6 @@ _Static_assert(0xE+0xC == 0xE + 0xC, "");
     "numbers.c:10:12: error: exponent has no digits" \
     "numbers.c:11:9: error: invalid suffix 'LLuf' on integer constant" \
     "numbers.c:16:16: error: invalid suffix '+0xC' on integer constant" \
+    "numbers.c:21:12: error: exponent has no digits" \
+    "numbers.c:22:12: error: invalid suffix 'pp-1' on floating constant" \