===================================================================
@@ -5957,6 +5957,25 @@ memory-mapped peripherals that may lie o
volatile int porta __attribute__((address (0x600)));
@end smallexample
+@item absdata
+@cindex @code{absdata} variable attribute, AVR
+Variables in static storage and with the @code{absdata} attribute can
+be accessed by the @code{LDS} and @code{STS} instructions which take
+absolute addresses.
+
+@itemize @bullet
+@item
+This attribute is only supported for the reduced AVR Tiny core
+like @code{ATtiny40}.
+
+@item
+There is currently no Binutils support for this attribute and the user has
+to make sure that respective data is located into an address range that
+can actually be handled by @code{LDS} and @code{STS}.
+This applies to addresses in the range @code{0x40}@dots{}@code{0xbf}.
+
+@end itemize
+
@end table
@node Blackfin Variable Attributes
===================================================================
@@ -81,9 +81,13 @@
/ SYMBOL_FLAG_MACH_DEP)
/* (AVR_TINY only): Symbol has attribute progmem */
-#define AVR_SYMBOL_FLAG_TINY_PM \
+#define AVR_SYMBOL_FLAG_TINY_PM \
(SYMBOL_FLAG_MACH_DEP << 7)
+/* (AVR_TINY only): Symbol has attribute absdata */
+#define AVR_SYMBOL_FLAG_TINY_ABSDATA \
+ (SYMBOL_FLAG_MACH_DEP << 8)
+
#define TINY_ADIW(REG1, REG2, I) \
"subi " #REG1 ",lo8(-(" #I "))" CR_TAB \
"sbci " #REG2 ",hi8(-(" #I "))"
@@ -1802,6 +1806,28 @@ avr_mode_dependent_address_p (const_rtx
}
+/* Return true if rtx X is a CONST_INT, CONST or SYMBOL_REF
+ address with the `absdata' variable attribute, i.e. respective
+ data can be read / written by LDS / STS instruction.
+ This is used only for AVR_TINY. */
+
+static bool
+avr_address_tiny_absdata_p (rtx x, machine_mode mode)
+{
+ if (CONST == GET_CODE (x))
+ x = XEXP (XEXP (x, 0), 0);
+
+ if (SYMBOL_REF_P (x))
+ return SYMBOL_REF_FLAGS (x) & AVR_SYMBOL_FLAG_TINY_ABSDATA;
+
+ if (CONST_INT_P (x)
+ && IN_RANGE (INTVAL (x), 0, 0xc0 - GET_MODE_SIZE (mode)))
+ return true;
+
+ return false;
+}
+
+
/* Helper function for `avr_legitimate_address_p'. */
static inline bool
@@ -1886,8 +1912,7 @@ avr_legitimate_address_p (machine_mode m
/* avrtiny's load / store instructions only cover addresses 0..0xbf:
IN / OUT range is 0..0x3f and LDS / STS can access 0x40..0xbf. */
- ok = (CONST_INT_P (x)
- && IN_RANGE (INTVAL (x), 0, 0xc0 - GET_MODE_SIZE (mode)));
+ ok = avr_address_tiny_absdata_p (x, mode);
}
if (avr_log.legitimate_address_p)
@@ -1929,8 +1954,7 @@ avr_legitimize_address (rtx x, rtx oldx,
if (AVR_TINY)
{
if (CONSTANT_ADDRESS_P (x)
- && !(CONST_INT_P (x)
- && IN_RANGE (INTVAL (x), 0, 0xc0 - GET_MODE_SIZE (mode))))
+ && ! avr_address_tiny_absdata_p (x, mode))
{
x = force_reg (Pmode, x);
}
@@ -9124,6 +9148,32 @@ avr_handle_fntype_attribute (tree *node,
}
static tree
+avr_handle_absdata_attribute (tree *node, tree name, tree /* args */,
+ int /* flags */, bool *no_add)
+{
+ location_t loc = DECL_SOURCE_LOCATION (*node);
+
+ if (AVR_TINY)
+ {
+ if (TREE_CODE (*node) != VAR_DECL
+ || (!TREE_STATIC (*node) && !DECL_EXTERNAL (*node)))
+ {
+ warning_at (loc, OPT_Wattributes, "%qE attribute only applies to"
+ " variables in static storage", name);
+ *no_add = true;
+ }
+ }
+ else
+ {
+ warning_at (loc, OPT_Wattributes, "%qE attribute only supported"
+ " for reduced Tiny cores", name);
+ *no_add = true;
+ }
+
+ return NULL_TREE;
+}
+
+static tree
avr_handle_addr_attribute (tree *node, tree name, tree args,
int flags ATTRIBUTE_UNUSED, bool *no_add)
{
@@ -9230,6 +9280,8 @@ avr_attribute_table[] =
false },
{ "address", 1, 1, false, false, false, avr_handle_addr_attribute,
false },
+ { "absdata", 0, 0, true, false, false, avr_handle_absdata_attribute,
+ false },
{ NULL, 0, 0, false, false, false, NULL, false }
};
@@ -9314,6 +9366,17 @@ avr_progmem_p (tree decl, tree attribute
}
+/* Return true if DECL has attribute `absdata' set. This function should
+ only be used for AVR_TINY. */
+
+static bool
+avr_decl_absdata_p (tree decl, tree attributes)
+{
+ return (TREE_CODE (decl) == VAR_DECL
+ && NULL_TREE != lookup_attribute ("absdata", attributes));
+}
+
+
/* Scan type TYP for pointer references to address space ASn.
Return ADDR_SPACE_GENERIC (i.e. 0) if all pointers targeting
the AS are also declared to be CONST.
@@ -9738,14 +9801,29 @@ avr_encode_section_info (tree decl, rtx
if (AVR_TINY
&& decl
&& VAR_DECL == TREE_CODE (decl)
- && -1 == avr_progmem_p (decl, DECL_ATTRIBUTES (decl))
&& MEM_P (rtl)
&& SYMBOL_REF_P (XEXP (rtl, 0)))
{
- /* Tag symbols for later addition of 0x4000 (AVR_TINY_PM_OFFSET). */
-
rtx sym = XEXP (rtl, 0);
- SYMBOL_REF_FLAGS (sym) |= AVR_SYMBOL_FLAG_TINY_PM;
+
+ if (-1 == avr_progmem_p (decl, DECL_ATTRIBUTES (decl)))
+ {
+ // Tag symbols for later addition of 0x4000 (AVR_TINY_PM_OFFSET).
+ SYMBOL_REF_FLAGS (sym) |= AVR_SYMBOL_FLAG_TINY_PM;
+ }
+
+ if (avr_decl_absdata_p (decl, DECL_ATTRIBUTES (decl)))
+ {
+ // May be accessed by LDS / STS.
+ SYMBOL_REF_FLAGS (sym) |= AVR_SYMBOL_FLAG_TINY_ABSDATA;
+ }
+
+ if (-1 == avr_progmem_p (decl, DECL_ATTRIBUTES (decl))
+ && avr_decl_absdata_p (decl, DECL_ATTRIBUTES (decl)))
+ {
+ error ("%q+D has incompatible attributes %qs and %qs",
+ decl, "progmem", "absdata");
+ }
}
}