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{ "id": 25854, "url": "https://patchwork.libcamera.org/api/patches/25854/?format=api", "web_url": "https://patchwork.libcamera.org/patch/25854/", "project": { "id": 1, "url": "https://patchwork.libcamera.org/api/projects/1/?format=api", "name": "libcamera", "link_name": "libcamera", "list_id": "libcamera_core", "list_email": "libcamera-devel@lists.libcamera.org", "web_url": "", "scm_url": "", "webscm_url": "" }, "msgid": "<20260120083952.15338-1-jacopo.mondi@ideasonboard.com>", "date": "2026-01-20T08:39:49", "name": "ipa: libipa: fixedpoint: Expand documentation on sign bit", "commit_ref": null, "pull_url": null, "state": "new", "archived": false, "hash": "5ec7744c7d74779cc9ad16089d47a14b92c59347", "submitter": { "id": 143, "url": "https://patchwork.libcamera.org/api/people/143/?format=api", "name": "Jacopo Mondi", "email": "jacopo.mondi@ideasonboard.com" }, "delegate": null, "mbox": "https://patchwork.libcamera.org/patch/25854/mbox/", "series": [ { "id": 5719, "url": "https://patchwork.libcamera.org/api/series/5719/?format=api", "web_url": "https://patchwork.libcamera.org/project/libcamera/list/?series=5719", "date": "2026-01-20T08:39:49", "name": "ipa: libipa: fixedpoint: Expand documentation on sign bit", "version": 1, "mbox": "https://patchwork.libcamera.org/series/5719/mbox/" } ], "comments": "https://patchwork.libcamera.org/api/patches/25854/comments/", "check": "pending", "checks": "https://patchwork.libcamera.org/api/patches/25854/checks/", "tags": {}, "headers": { "Return-Path": "<libcamera-devel-bounces@lists.libcamera.org>", "X-Original-To": "parsemail@patchwork.libcamera.org", "Delivered-To": "parsemail@patchwork.libcamera.org", "Received": [ "from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id 0076EC3220\n\tfor <parsemail@patchwork.libcamera.org>;\n\tTue, 20 Jan 2026 08:40:01 +0000 (UTC)", "from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id DA3DB61FBF;\n\tTue, 20 Jan 2026 09:40:00 +0100 (CET)", "from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[213.167.242.64])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 46DBC61F84\n\tfor <libcamera-devel@lists.libcamera.org>;\n\tTue, 20 Jan 2026 09:39:59 +0100 (CET)", "from ideasonboard.com (unknown\n\t[IPv6:2001:b07:6462:5de2:520d:d7a3:63ca:99e8])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id D00971733;\n\tTue, 20 Jan 2026 09:39:27 +0100 (CET)" ], "Authentication-Results": "lancelot.ideasonboard.com; dkim=pass (1024-bit key;\n\tunprotected) header.d=ideasonboard.com header.i=@ideasonboard.com\n\theader.b=\"OKYV0Zee\"; dkim-atps=neutral", "DKIM-Signature": "v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1768898368;\n\tbh=nhBEs/vulo4lXzSxImOJXBozPzzWK9oolqgqUjJbqac=;\n\th=From:To:Cc:Subject:Date:From;\n\tb=OKYV0ZeefAPIdtqU0IIwPSW6evxtE2DgKo5kv5G9wiRIrf4+ZMs3InwH6P70kpEDl\n\tNHJgsI/7nQjkVdr/Ir09HBd0lxenC9IXg8sTEQNuaIzcPM877Zx+Xrmv7J8hC74it0\n\tdonUnadRobvgvjLTDNM8qjERBRbi60EsC/oSXclI=", "From": "Jacopo Mondi <jacopo.mondi@ideasonboard.com>", "To": "libcamera-devel@lists.libcamera.org", "Cc": "Jacopo Mondi <jacopo.mondi@ideasonboard.com>,\n\tPaul Elder <paul.elder@ideasonboard.com>", "Subject": "[PATCH] ipa: libipa: fixedpoint: Expand documentation on sign bit", "Date": "Tue, 20 Jan 2026 09:39:49 +0100", "Message-ID": "<20260120083952.15338-1-jacopo.mondi@ideasonboard.com>", "X-Mailer": "git-send-email 2.52.0", "MIME-Version": "1.0", "Content-Transfer-Encoding": "8bit", "X-BeenThere": "libcamera-devel@lists.libcamera.org", "X-Mailman-Version": "2.1.29", "Precedence": "list", "List-Id": "<libcamera-devel.lists.libcamera.org>", "List-Unsubscribe": "<https://lists.libcamera.org/options/libcamera-devel>,\n\t<mailto:libcamera-devel-request@lists.libcamera.org?subject=unsubscribe>", "List-Archive": "<https://lists.libcamera.org/pipermail/libcamera-devel/>", "List-Post": "<mailto:libcamera-devel@lists.libcamera.org>", "List-Help": "<mailto:libcamera-devel-request@lists.libcamera.org?subject=help>", "List-Subscribe": "<https://lists.libcamera.org/listinfo/libcamera-devel>,\n\t<mailto:libcamera-devel-request@lists.libcamera.org?subject=subscribe>", "Errors-To": "libcamera-devel-bounces@lists.libcamera.org", "Sender": "\"libcamera-devel\" <libcamera-devel-bounces@lists.libcamera.org>" }, "content": "Converting numbers with a signed fixed-point representation to\nthe corresponding float value requires to include the sign bit in the\nwidth of the fixed-point integral part.\n\nClearly specify it in documentation.\n\nSigned-off-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>\n---\n src/ipa/libipa/fixedpoint.cpp | 22 +++++++++++++++++++++-\n 1 file changed, 21 insertions(+), 1 deletion(-)\n\n--\n2.52.0", "diff": "diff --git a/src/ipa/libipa/fixedpoint.cpp b/src/ipa/libipa/fixedpoint.cpp\nindex 6b698fc5d680..b37cdc43936f 100644\n--- a/src/ipa/libipa/fixedpoint.cpp\n+++ b/src/ipa/libipa/fixedpoint.cpp\n@@ -29,11 +29,31 @@ namespace ipa {\n /**\n * \\fn R fixedToFloatingPoint(T number)\n * \\brief Convert a fixed-point number to a floating point representation\n- * \\tparam I Bit width of the integer part of the fixed-point\n+ * \\tparam I Bit width of the integer part of the fixed-point including the\n+ * optional sign bit\n * \\tparam F Bit width of the fractional part of the fixed-point\n * \\tparam R Return type of the floating point representation\n * \\tparam T Input type of the fixed-point representation\n * \\param number The fixed point number to convert to floating point\n+ *\n+ * If the fixed-point representation is signed, the sign bit shall be included\n+ * in the \\a I template parameter that specifies the number of bits of the\n+ * integral part of the fixed-point representation.\n+ *\n+ * As an example, a value represented as signed fixed-point Q4.8 format can be\n+ * converted to its corresponding floating point representation as:\n+ *\n+ * \\code{.cpp}\n+ * double d = fixedToFloatingPoint<5, 8, double, uint16_t>(fixed);\n+ * \\endcode\n+ *\n+ * While a value represented as unsigned fixed-point Q4.8 format can be\n+ * converted as:\n+ *\n+ * \\code{.cpp}\n+ * double d = fixedToFloatingPoint<4, 8, double, uint16_t>(fixed);\n+ * \\endcode\n+ *\n * \\return The converted value\n */\n\n", "prefixes": [] }