dep: Add biscuit and riscv-disas

dep/biscuit/include/biscuit/isa.hpp

@@ -0,0 +1,49 @@
+#pragma once
+
+#include <cstdint>
+
+// Source file for general values and data structures
+// that don't fit a particular criteria related to the ISA.
+
+namespace biscuit {
+
+enum class FenceOrder : uint32_t {
+    W = 1, // Write
+    R = 2, // Read
+    O = 4, // Device Output
+    I = 8, // Device Input
+
+    RW = R | W,
+
+    IO = I | O,
+    IR = I | R,
+    IW = I | W,
+    IRW = I | R | W,
+
+    OI = O | I,
+    OR = O | R,
+    OW = O | W,
+    ORW = O | R | W,
+
+    IORW = I | O | R | W,
+};
+
+// Atomic ordering
+enum class Ordering : uint32_t {
+    None = 0,       // None
+    RL = 1,         // Release
+    AQ = 2,         // Acquire
+    AQRL = AQ | RL, // Acquire-Release
+};
+
+// Floating-point Rounding Mode
+enum class RMode : uint32_t {
+    RNE = 0b000, // Round to Nearest, ties to Even
+    RTZ = 0b001, // Round towards Zero
+    RDN = 0b010, // Round Down (towards negative infinity)
+    RUP = 0b011, // Round Up (towards positive infinity)
+    RMM = 0b100, // Round to Nearest, ties to Max Magnitude
+    DYN = 0b111, // Dynamic Rounding Mode
+};
+
+} // namespace biscuit