command: Support evaluating C expressions in DECL_CONSTANT()

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

scripts/buildcommands.py

@@ -101,19 +101,36 @@ Handlers.append(HandleStaticStrings())
 # Constants
 ######################################################################
 
+def decode_integer(value):
+    value = value.strip()
+    if len(value) != 7 or value[0] not in '-+':
+        error("Invalid encoded integer '%s'" % (value,))
+    out = sum([(ord(c) - 48) << (i*6) for i, c in enumerate(value[1:])])
+    if value[0] == '-':
+        out -= 1<<32
+    return out
+
 # Allow adding build time constants to the data dictionary
 class HandleConstants:
     def __init__(self):
         self.constants = {}
-        self.ctr_dispatch = { '_DECL_CONSTANT': self.decl_constant }
+        self.ctr_dispatch = {
+            '_DECL_CONSTANT': self.decl_constant,
+            '_DECL_CONSTANT_STR': self.decl_constant_str,
+        }
+    def set_value(self, name, value):
+        if name in self.constants and self.constants[name] != value:
+            error("Conflicting definition for constant '%s'" % name)
+        self.constants[name] = value
     def decl_constant(self, req):
+        name, value = req.split()[1:]
+        self.set_value(name, decode_integer(value))
+    def decl_constant_str(self, req):
         name, value = req.split()[1:]
         value = value.strip()
         if value.startswith('"') and value.endswith('"'):
             value = value[1:-1]
-        if name in self.constants and self.constants[name] != value:
-            error("Conflicting definition for constant '%s'" % name)
-        self.constants[name] = value
+        self.set_value(name, value)
     def update_data_dictionary(self, data):
         data['config'] = self.constants
     def generate_code(self, options):

src/command.h

@@ -7,17 +7,19 @@
 #include "ctr.h" // DECL_CTR
 
 // Declare a function to run when the specified command is received
+#define DECL_COMMAND_FLAGS(FUNC, FLAGS, MSG)                            \
+    DECL_CTR("_DECL_COMMAND " __stringify(FUNC) " " __stringify(FLAGS) " " MSG)
 #define DECL_COMMAND(FUNC, MSG)                 \
-    _DECL_COMMAND(FUNC, 0, MSG)
-#define DECL_COMMAND_FLAGS(FUNC, FLAGS, MSG)    \
-    _DECL_COMMAND(FUNC, FLAGS, MSG)
+    DECL_COMMAND_FLAGS(FUNC, 0, MSG)
 
 // Flags for command handler declarations.
 #define HF_IN_SHUTDOWN   0x01   // Handler can run even when in emergency stop
 
 // Declare a constant exported to the host
-#define DECL_CONSTANT(NAME, VALUE) _DECL_CONSTANT(NAME, __stringify(VALUE))
-#define DECL_CONSTANT_STR(NAME, VALUE) _DECL_CONSTANT(NAME, VALUE)
+#define DECL_CONSTANT(NAME, VALUE)                      \
+    DECL_CTR_INT("_DECL_CONSTANT " NAME, (VALUE))
+#define DECL_CONSTANT_STR(NAME, VALUE)                  \
+    DECL_CTR("_DECL_CONSTANT_STR " NAME " " VALUE)
 
 // Send an output message (and declare a static message type for it)
 #define output(FMT, args...)                    \
@@ -85,12 +87,6 @@ const struct command_encoder *ctr_lookup_encoder(const char *str);
 const struct command_encoder *ctr_lookup_output(const char *str);
 uint8_t ctr_lookup_static_string(const char *str);
 
-#define _DECL_COMMAND(FUNC, FLAGS, MSG)                                 \
-    DECL_CTR("_DECL_COMMAND " __stringify(FUNC) " " __stringify(FLAGS) " " MSG)
-
-#define _DECL_CONSTANT(NAME, VALUE)             \
-    DECL_CTR("_DECL_CONSTANT " NAME " " VALUE)
-
 #define _DECL_ENCODER(FMT) ({                   \
     DECL_CTR("_DECL_ENCODER " FMT);             \
     ctr_lookup_encoder(FMT); })

src/ctr.h

@@ -14,4 +14,17 @@
     static char __PASTE(_DECLS_, __LINE__)[] __attribute__((used))      \
         __section(".compile_time_request") = (REQUEST)
 
+#define CTR_INT(V, S) ((((uint32_t)(V) >> S) & 0x3f) + 48)
+
+// Declare a compile time request with an integer expression
+#define DECL_CTR_INT(REQUEST, VALUE)                            \
+    static struct { char _r[sizeof(REQUEST)]; char _v[8]; }     \
+        __PASTE(_DECLI_, __LINE__) __attribute__((used))        \
+            __section(".compile_time_request") = {              \
+            REQUEST " ", {                                      \
+                (VALUE) < 0 ? '-' : '+',                        \
+                CTR_INT((VALUE),0), CTR_INT((VALUE),6),         \
+                CTR_INT((VALUE),12), CTR_INT((VALUE),18),       \
+                CTR_INT((VALUE),24), CTR_INT((VALUE),30), 0 } }
+
 #endif // ctr.h