docs: add long_name, description for Q instructions

Descriptions are taken verbatim from the RISC-V ISA specification where
applicable, and are marked `normative: true` accordingly. Naming and
format follow UnifiedDB conventions.

Author: sudo-abdullah

backends/instructions_appendix/all_instructions.golden.adoc

@@ -6,7 +6,7 @@
 $schema: "inst_schema.json#"
 kind: instruction
 name: fadd.q
-long_name: Floating-point Add Quad-precision
+long_name: Floating-point Add Quad-Precision
 description:
   - id: inst-fadd.q-behaviour
     normative: false

spec/std/isa/inst/Q/fadd.q.yaml

@@ -6,9 +6,35 @@
 $schema: "inst_schema.json#"
 kind: instruction
 name: fclass.q
-long_name: No synopsis available
-description: |
-  No description available.
+long_name: Floating-Point Classify Quad-Precision
+description:
+  - id: inst-fclass.q-behaviour
+    normative: false
+    text: |
+      The `fclass.q` instruction examines the value in floating-point register `rs1` and writes to integer
+      register `rd` a 10-bit mask that indicates the class of the floating-point number.
+
+      The format of the mask is described in table given below. The corresponding bit in `rd`
+      will be set if the property is true and clear otherwise. All other bits in `rd` are cleared.
+
+      Note that exactly one bit in `rd` will be set. `fclass.q` does not set the floating-point
+      exception flags.
+
+      .Format of result of `fclass` instruction.
+      [%autowidth,float="center",align="center",cols="^,<",options="header",]
+      |===
+      |_xd_ bit |Meaning
+      |0 |_fs1_ is latexmath:[$-\infty$].
+      |1 |_fs1_ is a negative normal number.
+      |2 |_fs1_ is a negative subnormal number.
+      |3 |_fs1_ is latexmath:[$-0$].
+      |4 |_fs1_ is latexmath:[$+0$].
+      |5 |_fs1_ is a positive subnormal number.
+      |6 |_fs1_ is a positive normal number.
+      |7 |_fs1_ is latexmath:[$+\infty$].
+      |8 |_fs1_ is a signaling NaN.
+      |9 |_fs1_ is a quiet NaN.
+      |===
 definedBy: Q
 assembly: xd, fs1
 encoding:

spec/std/isa/inst/Q/fclass.q.yaml

@@ -6,7 +6,7 @@
 $schema: "inst_schema.json#"
 kind: instruction
 name: fcvt.d.q
-long_name: Floating-point Convert Quad-precision to Double-precision
+long_name: Floating-Point Convert Quad-Precision to Double-Precision
 description:
   - id: inst-fcvt.d.q-behaviour
     normative: false

spec/std/isa/inst/Q/fcvt.d.q.yaml

@@ -6,7 +6,7 @@
 $schema: "inst_schema.json#"
 kind: instruction
 name: fcvt.l.q
-long_name: Floating-point Convert Quad-precision to Long
+long_name: Floating-Point Convert Quad-Precision to Long
 description:
   - id: inst-fcvt.l.q-behaviour
     normative: false

spec/std/isa/inst/Q/fcvt.l.q.yaml

@@ -6,7 +6,7 @@
 $schema: "inst_schema.json#"
 kind: instruction
 name: fcvt.lu.q
-long_name: Floating-point Convert Quad-precision to Unsigned Long
+long_name: Floating-Point Convert Quad-Precision to Unsigned Long
 description:
   - id: inst-fcvt.lu.q-behaviour
     normative: false

spec/std/isa/inst/Q/fcvt.lu.q.yaml

@@ -6,7 +6,7 @@
 $schema: "inst_schema.json#"
 kind: instruction
 name: fcvt.q.d
-long_name: Floating-point Convert Double-precision to Quad-precision
+long_name: Floating-Point Convert Double-Precision to Quad-Precision
 description:
   - id: inst-fcvt.q.d-behaviour
     normative: false

spec/std/isa/inst/Q/fcvt.q.d.yaml

@@ -6,7 +6,7 @@
 $schema: "inst_schema.json#"
 kind: instruction
 name: fcvt.q.l
-long_name: Floating-point Convert Long to Quad-precision
+long_name: Floating-Point Convert Long to Quad-Precision
 description:
   - id: inst-fcvt.q.l-behaviour
     normative: false

spec/std/isa/inst/Q/fcvt.q.l.yaml

@@ -6,7 +6,7 @@
 $schema: "inst_schema.json#"
 kind: instruction
 name: fcvt.q.lu
-long_name: Floating-point Convert Unsigned Long to Quad-precision
+long_name: Floating-Point Convert Unsigned Long to Quad-Precision
 description:
   - id: inst-fcvt.q.lu-behaviour
     normative: false

spec/std/isa/inst/Q/fcvt.q.lu.yaml

@@ -6,7 +6,7 @@
 $schema: "inst_schema.json#"
 kind: instruction
 name: fcvt.q.s
-long_name: Floating-point Convert Single-precision to Quad-precision
+long_name: Floating-Point Convert Single-Precision to Quad-Precision
 description:
   - id: inst-fcvt.q.s-behaviour
     normative: false