Implement complete Floating-Point word set, 70+ float words

Separate float stack with fsp global, IEEE 754 double precision.
Stack ops: FDROP FDUP FSWAP FOVER FROT FDEPTH
Arithmetic: F+ F- F* F/ FNEGATE FABS FMAX FMIN FSQRT FLOOR FROUND F**
Comparisons: F0= F0< F= F< F~
Memory: F@ F! SF@ SF! DF@ DF! FLOAT+ FLOATS FALIGNED FALIGN
Conversions: D>F F>D S>F F>S
Trig: FSIN FCOS FTAN FASIN FACOS FATAN FATAN2 FSINCOS
Exp/Log: FEXP FEXPM1 FLN FLNP1 FLOG FALOG
Hyperbolic: FSINH FCOSH FTANH FASINH FACOSH FATANH
I/O: F. FE. FS. REPRESENT >FLOAT PRECISION SET-PRECISION
Defining: FVARIABLE FCONSTANT FVALUE FLITERAL
Float literal parsing (1E, 1.5E2, -3.14E0 format)
299 unit tests + 11 compliance tests, 0 errors on float test suite

crates/core/src/codegen.rs

@@ -29,6 +29,10 @@ const DSP: u32 = 0;
 /// Index of the `$rsp` global (return stack pointer).
 const RSP: u32 = 1;
 
+/// Index of the `$fsp` global (float stack pointer).
+#[allow(dead_code)]
+const FSP: u32 = 2;
+
 /// Index of the imported function table.
 const TABLE: u32 = 0;
 
@@ -795,6 +799,15 @@ pub fn compile_word(
             shared: false,
         }),
     );
+    imports.import(
+        "env",
+        "fsp",
+        EntityType::Global(GlobalType {
+            val_type: ValType::I32,
+            mutable: true,
+            shared: false,
+        }),
+    );
     imports.import(
         "env",
         "table",
@@ -871,7 +884,7 @@ mod tests {
     use super::*;
     use crate::dictionary::WordId;
     use crate::ir::IrOp;
-    use crate::memory::{DATA_STACK_TOP, RETURN_STACK_TOP};
+    use crate::memory::{DATA_STACK_TOP, FLOAT_STACK_TOP, RETURN_STACK_TOP};
 
     fn default_config() -> CodegenConfig {
         CodegenConfig {
@@ -1133,6 +1146,13 @@ mod tests {
         )
         .unwrap();
 
+        let fsp = Global::new(
+            &mut store,
+            wasmtime::GlobalType::new(ValType::I32, Mutability::Var),
+            Val::I32(FLOAT_STACK_TOP as i32),
+        )
+        .unwrap();
+
         let table = Table::new(
             &mut store,
             wasmtime::TableType::new(RefType::FUNCREF, 16, None),
@@ -1152,6 +1172,7 @@ mod tests {
                 memory.into(),
                 dsp.into(),
                 rsp.into(),
+                fsp.into(),
                 table.into(),
             ],
         )