Merge pull request #397 from pguyot/w45/add-missing-opcodes

Add missing FP opcodes

These opcodes are officially supported since R8. `fclearerror/0` and
`fcheckerror/1` are noops as they are no longer implemented in OTP24 and the
error is always checked by other OP_F* opcodes.

Compiler support for `STDC FENV_ACCESS` pragma is checked and it is assumed
that it means the compiler is conforming to C11 FENV support when the pragma
is accepted. In this case, exception are checked using C11 floating point
environment functions. If the pragma is unknown, `isfinite(3)` is used instead,
assuming a non finite result is an error. This is what BEAM does on Unix.

No `badarith` exception is raised on underflow divisions, to be compatible
with BEAM (which cannot check that as it uses `isfinite(3)`). The only checked
exceptions are overflow and division by zero.

The tests were updated to actually generate the FP opcodes with OTP21-24
compilers. A new test was added for div.

CI is updated to usually not use AVM_DISABLE_FP option. Only one
configuration is maintained shall we decide to keep the option.

Also assert types of operands at load time and ignore them at execution time.
Also simplify macros by getting rid of the duplicate last parameter.

These changes are made under both the "Apache 2.0" and the "GNU Lesser General
Public License 2.1 or later" license terms (dual license).

SPDX-License-Identifier: Apache-2.0 OR LGPL-2.1-or-later

Author: bettio

.github/workflows/build-and-test.yaml

@@ -93,19 +93,15 @@ jobs:
 
         - otp: "21"
           elixir_version: "1.7"
-          cmake_opts: ""
 
         - otp: "22"
           elixir_version: "1.8"
-          cmake_opts: "-DAVM_DISABLE_FP=on"
 
         - otp: "23"
-          elixir_version: "1.10.4"
-          cmake_opts: "-DAVM_DISABLE_FP=on"
+          elixir_version: "1.11"
 
         - otp: "24"
-          elixir_version: "1.11"
-          cmake_opts: "-DAVM_DISABLE_FP=on"
+          elixir_version: "1.14"
 
         - os: "ubuntu-18.04"
           cc: "gcc-4.8"
@@ -123,13 +119,22 @@ jobs:
           cxx: "g++-10"
           cflags: "-m32 -O3"
           otp: "23"
-          elixir_version: "1.10.4"
-          cmake_opts: "-DOPENSSL_CRYPTO_LIBRARY=/usr/lib/i386-linux-gnu/libcrypto.so
-          -DAVM_DISABLE_FP=on"
+          elixir_version: "1.11"
+          cmake_opts: "-DOPENSSL_CRYPTO_LIBRARY=/usr/lib/i386-linux-gnu/libcrypto.so"
           arch: "i386"
           compiler_pkgs: "gcc-10 g++-10 gcc-10-multilib g++-10-multilib libc6-dev-i386
           libc6-dbg:i386 zlib1g-dev:i386 libssl-dev:i386"
 
+        # keep one FP disabled configuration
+        - os: "ubuntu-20.04"
+          cc: "gcc-10"
+          cxx: "g++-10"
+          cflags: "-O3"
+          otp: "24"
+          elixir_version: "1.14"
+          cmake_opts: "-DAVM_DISABLE_FP=on"
+          compiler_pkgs: "gcc-10 g++-10"
+
     env:
       CC: ${{ matrix.cc }}
       CXX: ${{ matrix.cxx }}

CHANGELOG.md

@@ -32,6 +32,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Added support for the OTP `math` module
 - Added support for `erlang:integer_to_list/2` and `erlang:integer_to_binary/2`
 - Added functions `esp:sleep_enable_ext0_wakeup/2` and `esp:sleep_enable_ext1_wakeup/2.`
+- Added support for FP opcodes 94-102 thus removing the need for `AVM_DISABLE_FP=On` with OTP-22+
 
 ### Fixed
 - Fixed issue with formatting integers with io:format() on STM32 platform

src/libAtomVM/context.c

@@ -20,6 +20,9 @@
 
 #include "context.h"
 
+#include <fenv.h>
+#include <math.h>
+
 #include "dictionary.h"
 #include "globalcontext.h"
 #include "list.h"
@@ -55,6 +58,10 @@ Context *context_new(GlobalContext *glb)
 
     context_clean_registers(ctx, 0);
 
+#ifndef AVM_NO_FP
+    ctx->fr = NULL;
+#endif
+
     ctx->min_heap_size = 0;
     ctx->max_heap_size = 0;
     ctx->has_min_heap_size = 0;
@@ -111,6 +118,9 @@ Context *context_new(GlobalContext *glb)
 
 void context_destroy(Context *ctx)
 {
+#ifndef AVM_NO_FP
+    free(ctx->fr);
+#endif
     list_remove(&ctx->processes_table_head);
 
     memory_sweep_mso_list(ctx->mso_list);

src/libAtomVM/context.h

@@ -71,6 +71,10 @@ struct Context
 
     term x[MAX_REG];
 
+#ifndef AVM_NO_FP
+    avm_float_t *fr;
+#endif
+
     term *heap_start;
     term *stack_base;
     term *heap_ptr;
@@ -163,6 +167,23 @@ Context *context_new(GlobalContext *glb);
  */
 void context_destroy(Context *c);
 
+#ifndef AVM_NO_FP
+/**
+ * @brief Ensure we have FP registers, allocating them if necessary.
+ * @param c context fo allocate FP registers for
+ */
+static inline void context_ensure_fpregs(Context *c)
+{
+    if (UNLIKELY(c->fr == NULL)) {
+        c->fr = (avm_float_t *) malloc(sizeof(avm_float_t) * MAX_REG);
+        if (UNLIKELY(c->fr == NULL)) {
+            fprintf(stderr, "Could not allocate FP registers\n");
+            AVM_ABORT();
+        }
+    }
+}
+#endif
+
 /**
  * @brief Starts executing a function
  *

src/libAtomVM/opcodes.h

@@ -87,6 +87,15 @@
 #define OP_BS_PUT_INTEGER 89
 #define OP_BS_PUT_BINARY 90
 #define OP_BS_PUT_STRING 92
+#define OP_FCLEARERROR 94
+#define OP_FCHECKERROR 95
+#define OP_FMOVE 96
+#define OP_FCONV 97
+#define OP_FADD 98
+#define OP_FSUB 99
+#define OP_FMUL 100
+#define OP_FDIV 101
+#define OP_FNEGATE 102
 #define OP_MAKE_FUN2 103
 #define OP_TRY 104
 #define OP_TRY_END 105