OpenE2K/binutils-gdb
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Clarify the address and pointer conversions on AVR.

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This patch adds additional comments about the conversion of addresses to
pointers and vice-versa on AVR.

Special conversion needs to be done when dealing with an address in the
flash address space, where both code and read-only data can be stored.
Code and data pointers to flash are not addressed the same way:

A code pointer is 16 bit addressed.  A data pointer is 8 bit addressed,
even if the data is in flash.

2014-07-25  Pierre Langlois  <pierre.langlois@embecosm.com>

	* avr-tdep.c (avr_address_to_pointer): Clarify the conversion in the
	comments.
	(avr_pointer_to_address): Likewise.
This commit is contained in:
Pierre Langlois 2014-07-25 14:45:03 +01:00
parent c3f814a143
commit 7d0d9d2bee
2 changed files with 18 additions and 5 deletions
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6
gdb/ChangeLog
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@ -1,3 +1,9 @@
2014-07-25 Pierre Langlois <pierre.langlois@embecosm.com>
* avr-tdep.c (avr_address_to_pointer): Clarify the conversion in the
comments.
(avr_pointer_to_address): Likewise.
2014-07-24 Tom Tromey <tromey@redhat.com>
* monitor.c (compile_pattern): Update.

17
gdb/avr-tdep.c
View File

@ -308,7 +308,7 @@ avr_address_to_pointer (struct gdbarch *gdbarch,
/* Is it a data address in flash? */
if (AVR_TYPE_ADDRESS_CLASS_FLASH (type))
{
/* A data address in flash is always byte addressed. */
/* A data pointer in flash is byte addressed. */
store_unsigned_integer (buf, TYPE_LENGTH (type), byte_order,
avr_convert_iaddr_to_raw (addr));
}
@ -316,8 +316,8 @@ avr_address_to_pointer (struct gdbarch *gdbarch,
else if (TYPE_CODE (TYPE_TARGET_TYPE (type)) == TYPE_CODE_FUNC
|| TYPE_CODE (TYPE_TARGET_TYPE (type)) == TYPE_CODE_METHOD)
{
/* A code address, either a function pointer or the program counter, is
word (16 bits) addressed. */
/* A code pointer is word (16 bits) addressed. We shift the address down
by 1 bit to convert it to a pointer. */
store_unsigned_integer (buf, TYPE_LENGTH (type), byte_order,
avr_convert_iaddr_to_raw (addr >> 1));
}
@ -339,12 +339,19 @@ avr_pointer_to_address (struct gdbarch *gdbarch,
/* Is it a data address in flash? */
if (AVR_TYPE_ADDRESS_CLASS_FLASH (type))
return avr_make_iaddr (addr);
{
/* A data pointer in flash is already byte addressed. */
return avr_make_iaddr (addr);
}
/* Is it a code address? */
else if (TYPE_CODE (TYPE_TARGET_TYPE (type)) == TYPE_CODE_FUNC
|| TYPE_CODE (TYPE_TARGET_TYPE (type)) == TYPE_CODE_METHOD
|| TYPE_CODE_SPACE (TYPE_TARGET_TYPE (type)))
return avr_make_iaddr (addr << 1);
{
/* A code pointer is word (16 bits) addressed so we shift it up
by 1 bit to convert it to an address. */
return avr_make_iaddr (addr << 1);
}
else
return avr_make_saddr (addr);
}