avr/bootloader
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

pureboot: the poll-cost lookup rides the baud parameter

Browse Source 
usart_of<0> is an incomplete type on the USART-less chips, and a static
member initializer with only non-dependent operands is checked when the
template is parsed, not when it is instantiated — so the address probe
broke every tiny build without hardware_link ever being named. The
lookup moves into a member function template taking the link's own baud
parameter, the dependence carrier that defers it to instantiation.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
This commit is contained in:
BlackMark
2026-07-30 16:13:44 +02:00
parent 459d463283
commit aa66cfccff
1 changed files with 9 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files

10
pureboot/pureboot.cpp
View File

@@ -177,7 +177,15 @@ struct hardware_link {
// bit-addressable I/O (the classic megas), lds + skip (4) in extended
// I/O. A uint32_t countdown pays one more sbci — window_polls() adds it
// where the count forces the wide type. Held by the pureboot.window gate.
static constexpr std::uint8_t poll_cycles = avr::hw::usart_of<usart_unit>::ucsra::addr < 0x40 ? 7 : 9;
// The lookup rides the baud parameter so it stays dependent: the trait is
// an incomplete type on the USART-less chips, which parse this template
// without ever instantiating it.
template <avr::baud_t Baud, typename U = avr::hw::usart_of<usart_unit>>
static consteval std::uint8_t poll_cost()
{
return U::ucsra::addr < 0x40 ? 7 : 9;
}
static constexpr std::uint8_t poll_cycles = poll_cost<B>();
static void init()
{