Reduce stack usage #1
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Instead of copying the remaining data out of the APDU buffer and back into it, we can use a memmove to move it to the beginning and truncate the buffer afterwards. This reduces the stack usage on lpc55 from 21 kB to 6 kB.
This halfs stack usage on the lpc55.
This patch replaces the Responder::take_request in ApduDispatch::check_for_request with Responder::request, reducing stack usage from 12 kB to 6 kB.
sosthene-nitrokey
approved these changes
Nov 8, 2023
| (message, Interface::Contact) | ||
| } else { | ||
| return RequestType::None; | ||
| }; | ||
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| // Parse the message as an APDU. | ||
| match Self::parse_apdu::<{ interchanges::SIZE }>(&message) { | ||
| match Self::parse_apdu::<{ interchanges::SIZE }>(message) { |
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When we update iso7816 we can use CommandView here and avoid copying the APDU data
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I think I checked that but there was some reason why it did not make a big difference. Maybe the data does not live long enough? I’ll have another look.
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I think I made a mistake when changing the buffer sizes. At least I remember running into a panic the last time I tested this change. I have to test it again before merging it. |
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This PR contains several patches that reduce stack usage on the lpc55:
ApduDispatch::handle_responseApduDispatch::check_for_requestApduBuffer::request