Ian,
Just from a purely AVR architecture point of view, the AVR_HAVE_RAMPD
#define indicates that the AVR chip in question supports the "RAMP"
paging register, described as follows:
*RAMPD*
Register concatenated with the Z-register enabling direct addressing
of the whole data space on MCU
Browsing the GCC source, I found this in gcc/config/avr/avr.c
if (AVR_HAVE_RAMPZ
&& TEST_HARD_REG_BIT (set, REG_Z)
&& TEST_HARD_REG_BIT (set, REG_Z + 1))
{
emit_push_sfr (rampz_rtx, false /* frame */, AVR_HAVE_RAMPD,
treg);
}
I wont pretend to fully
