Description
Hi @cmaglie, your changes to stk500v2.c in arduino/Arduino@06ee62a breaks the monitor as casting the PROGMEM strings such as gTextMsg_Explorer in devices with more than 64 kB of flash to uint16_t, causes the upper bits which are supposed to go into the ZRAMP register to go to zero, incorrectly addressing the application space instead of bootloader space.
I have verified all this in assembly, and resolved the issue by reverting this cast back to a uint32_t. RunMonitor now prints the strings correctly on the ATmega2560.
@cmaglie, @damellis, @zeveland: Please advise me how you want to proceed. I am using a cleanly built GCC version 4.8.2 with AVRLIBC 1.8.0.
The following doxygen comments from the macros confirm that pgm_read_byte_far should always take a 32 bit address. pgm_read_byte_near is more efficient but doesn't support 32 bit addressing.
/** \ingroup avr_pgmspace
\def pgm_read_byte(address_short)
Read a byte from the program space with a 16-bit (near) address.
\note The address is a byte address.
The address is in the program space. */
#define pgm_read_byte(address_short) pgm_read_byte_near(address_short)/** \ingroup avr_pgmspace
\def pgm_read_byte_far(address_long)
Read a byte from the program space with a 32-bit (far) address.
\note The address is a byte address.
The address is in the program space. */
#define pgm_read_byte_far(address_long) __ELPM((uint32_t)(address_long))