unix: machine_mem improvements

This basically introduces the MICROPY_MACHINE_MEM_GET_READ_ADDR
and MICROPY_MACHINE_MEM_GET_WRITE_ADDR macros. If one of them is
not defined, then a default identity function is provided.

extmod/machine_mem.c

@@ -25,9 +25,35 @@
  */
 
 #include "extmod/machine_mem.h"
+#include "py/nlr.h"
 
 #if MICROPY_PY_MACHINE
 
+// If you wish to override the functions for mapping the machine_mem read/write
+// address, then add a #define for MICROPY_MACHINE_MEM_GET_READ_ADDR and/or
+// MICROPY_MACHINE_MEM_GET_WRITE_ADDR in yopur mpconfigport.h. Since the
+// prototypes are identical, it is allowable for both of the macros to evaluate
+// the to same function.
+//
+// It is expected that the modmachine.c file for a given port will provide the
+// implementations, if the default implementation isn't used.
+
+#if !defined(MICROPY_MACHINE_MEM_GET_READ_ADDR) || !defined(MICROPY_MACHINE_MEM_GET_WRITE_ADDR)
+STATIC uintptr_t machine_mem_get_addr(mp_obj_t addr_o, uint align) {
+    uintptr_t addr = mp_obj_int_get_truncated(addr_o);
+    if ((addr & (align - 1)) != 0) {
+        nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError, "address %08x is not aligned to %d bytes", addr, align));
+    }
+    return addr;
+}
+#if !defined(MICROPY_MACHINE_MEM_GET_READ_ADDR)
+#define MICROPY_MACHINE_MEM_GET_READ_ADDR machine_mem_get_addr
+#endif
+#if !defined(MICROPY_MACHINE_MEM_GET_WRITE_ADDR)
+#define MICROPY_MACHINE_MEM_GET_WRITE_ADDR machine_mem_get_addr
+#endif
+#endif
+
 STATIC void machine_mem_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
     (void)kind;
     machine_mem_obj_t *self = MP_OBJ_TO_PTR(self_in);
@@ -42,7 +68,7 @@ STATIC mp_obj_t machine_mem_subscr(mp_obj_t self_in, mp_obj_t index, mp_obj_t va
         return MP_OBJ_NULL; // op not supported
     } else if (value == MP_OBJ_SENTINEL) {
         // load
-        uintptr_t addr = machine_mem_get_read_addr(index, self->elem_size);
+        uintptr_t addr = MICROPY_MACHINE_MEM_GET_READ_ADDR(index, self->elem_size);
         uint32_t val;
         switch (self->elem_size) {
             case 1: val = (*(uint8_t*)addr); break;
@@ -52,7 +78,7 @@ STATIC mp_obj_t machine_mem_subscr(mp_obj_t self_in, mp_obj_t index, mp_obj_t va
         return mp_obj_new_int(val);
     } else {
         // store
-        uintptr_t addr = machine_mem_get_write_addr(index, self->elem_size);
+        uintptr_t addr = MICROPY_MACHINE_MEM_GET_WRITE_ADDR(index, self->elem_size);
         uint32_t val = mp_obj_get_int(value);
         switch (self->elem_size) {
             case 1: (*(uint8_t*)addr) = val; break;

extmod/machine_mem.h

@@ -25,8 +25,8 @@
  */
 
 
-#ifndef MICROPY_EXTMOD_MACHINE_MEM
-#define MICROPY_EXTMOD_MACHINE_MEM
+#ifndef __MICROPY_INCLUDED_EXTMOD_MACHINE_MEM_H__
+#define __MICROPY_INCLUDED_EXTMOD_MACHINE_MEM_H__
 
 #include "py/obj.h"
 
@@ -41,10 +41,11 @@ extern const machine_mem_obj_t machine_mem8_obj;
 extern const machine_mem_obj_t machine_mem16_obj;
 extern const machine_mem_obj_t machine_mem32_obj;
 
-// It is expected that a port will provide the following 2 functions.
-// We define the prototypes here, but the modmachine.c file for a port should
-// provide the implementation
-uintptr_t machine_mem_get_read_addr(mp_obj_t addr_o, uint align);
-uintptr_t machine_mem_get_write_addr(mp_obj_t addr_o, uint align);
+#if defined(MICROPY_MACHINE_MEM_GET_READ_ADDR)
+uintptr_t MICROPY_MACHINE_MEM_GET_READ_ADDR(mp_obj_t addr_o, uint align);
+#endif
+#if defined(MICROPY_MACHINE_MEM_GET_WRITE_ADDR)
+uintptr_t MICROPY_MACHINE_MEM_GET_WRITE_ADDR(mp_obj_t addr_o, uint align);
+#endif
 
-#endif /*  MICROPY_EXTMOD_MACHINE_MEM */
+#endif // __MICROPY_INCLUDED_EXTMOD_MACHINE_MEM_H__

unix/modmachine.c

@@ -42,7 +42,7 @@
 
 #if MICROPY_PY_MACHINE
 
-uintptr_t machine_mem_get_read_addr(mp_obj_t addr_o, uint align) {
+uintptr_t mod_machine_mem_get_addr(mp_obj_t addr_o, uint align) {
     uintptr_t addr = mp_obj_int_get_truncated(addr_o);
     if ((addr & (align - 1)) != 0) {
         nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError, "address %08x is not aligned to %d bytes", addr, align));
@@ -72,10 +72,6 @@ uintptr_t machine_mem_get_read_addr(mp_obj_t addr_o, uint align) {
     return addr;
 }
 
-uintptr_t machine_mem_get_write_addr(mp_obj_t addr_o, uint align) {
-    return machine_mem_get_read_addr(addr_o, align);
-}
-
 STATIC const mp_rom_map_elem_t machine_module_globals_table[] = {
     { MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_umachine) },
 

unix/mpconfigport.h

@@ -108,6 +108,8 @@
 #define MICROPY_PY_USELECT          (1)
 #endif
 #define MICROPY_PY_MACHINE          (1)
+#define MICROPY_MACHINE_MEM_GET_READ_ADDR   mod_machine_mem_get_addr
+#define MICROPY_MACHINE_MEM_GET_WRITE_ADDR  mod_machine_mem_get_addr
 
 // Define to MICROPY_ERROR_REPORTING_DETAILED to get function, etc.
 // names in exception messages (may require more RAM).