From 85176ef10a795dc2ab50aa9ca8a4e0849bf58f2a Mon Sep 17 00:00:00 2001
From: Rangi <35663410+Rangi42@users.noreply.github.com>
Date: Fri, 29 Aug 2025 14:23:49 -0400
Subject: [PATCH] Fix `q` format spec (#1811)

---
 man/rgbasm.5                | 9 ++++++++-
 src/asm/format.cpp          | 6 +++---
 test/asm/invalid-format.asm | 2 +-
 test/asm/invalid-format.err | 4 +++-
 test/asm/invalid-format.out | 2 +-
 5 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/man/rgbasm.5 b/man/rgbasm.5
index bb4ee85b..a2ab7e83 100644
--- a/man/rgbasm.5
+++ b/man/rgbasm.5
@@ -196,12 +196,19 @@ If specified, pads right-aligned numbers with zeros instead of spaces.
 If specified, pads the value to this width, right-aligned with spaces by default.
 .It Ql <frac> Ta May be
 .Ql \&.
-followed by one or more
+followed by zero or more
 .Ql 0
 \[en]
 .Ql 9 .
 If specified, prints this many fractional digits of a fixed-point number.
 Defaults to 5 digits, maximum 255 digits.
+(A
+.Ql \&.
+followed by zero
+.Ql 0
+\[en]
+.Ql 9
+prints zero fractional digits.)
 .It Ql <prec> Ta May be
 .Ql q
 followed by one or more
diff --git a/src/asm/format.cpp b/src/asm/format.cpp
index ecea78f5..74223b0f 100644
--- a/src/asm/format.cpp
+++ b/src/asm/format.cpp
@@ -77,9 +77,9 @@ void FormatSpec::useCharacter(int c) {
 		}
 		return;
 
-	// width
+	// frac
 	case '.':
-		if (state > FORMAT_WIDTH) {
+		if (state >= FORMAT_FRAC) {
 			break;
 		}
 		state = FORMAT_FRAC;
@@ -88,7 +88,7 @@ void FormatSpec::useCharacter(int c) {
 
 	// prec
 	case 'q':
-		if (state > FORMAT_PREC) {
+		if (state >= FORMAT_PREC) {
 			break;
 		}
 		state = FORMAT_PREC;
diff --git a/test/asm/invalid-format.asm b/test/asm/invalid-format.asm
index 98f31c34..335879ee 100644
--- a/test/asm/invalid-format.asm
+++ b/test/asm/invalid-format.asm
@@ -2,7 +2,7 @@ println STRFMT("%+d %++d", 42, 42)
 println STRFMT("%#x %##x", 42, 42)
 println STRFMT("%-4d %--4d", 42, 42)
 println STRFMT("%.f %..f", 42.0, 42.0)
-println STRFMT("%qf %q.16f", 42.0, 42.0)
+println STRFMT("%qf %q.16f %qq16f", 42.0, 42.0, 42.0)
 
 DEF N = 42
 println "{5d:N} {5d5:N}"
diff --git a/test/asm/invalid-format.err b/test/asm/invalid-format.err
index d2efb4f6..3a63fb62 100644
--- a/test/asm/invalid-format.err
+++ b/test/asm/invalid-format.err
@@ -10,6 +10,8 @@ error: Fixed-point constant precision 0 invalid, defaulting to 16
     at invalid-format.asm(5)
 error: STRFMT: Invalid format spec for argument 2
     at invalid-format.asm(5)
+error: STRFMT: Invalid format spec for argument 3
+    at invalid-format.asm(5)
 error: Invalid format spec "5d5"
     at invalid-format.asm(8)
 error: Invalid format spec "xx"
@@ -28,4 +30,4 @@ error: Formatting type 'd' with fractional width
     at invalid-format.asm(17)
 error: Formatting type 'd' with fractional precision
     at invalid-format.asm(18)
-Assembly aborted with 15 errors!
+Assembly aborted with 16 errors!
diff --git a/test/asm/invalid-format.out b/test/asm/invalid-format.out
index 8ab38603..005108f7 100644
--- a/test/asm/invalid-format.out
+++ b/test/asm/invalid-format.out
@@ -2,7 +2,7 @@
 $2a %x
 42   %4d
 42 %f
-42.00000 %16f
+42.00000 %16f %16f
    42    42
 2a 2a
 hello