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Merge pull request #3048 from DRracer/bootappflags-bad-addr 

Fix flashing languages with inline wdr instructions
This commit is contained in:
DRracer 2021-03-03 13:46:08 +01:00 committed by GitHub
parent c1849f5cc2 8ced0579d6
commit 073cbe0339
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GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 11 additions and 6 deletions
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17
Firmware/optiboot_w25x20cl.cpp
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@ -115,8 +115,6 @@ uint8_t optiboot_w25x20cl_enter()
// If the magic is not received on time, or it is not received correctly, continue to the application.
{
wdt_reset();
unsigned long boot_timeout = 2000000;
unsigned long boot_timer = 0;
const char *ptr = entry_magic_send;
const char *end = strlen_P(entry_magic_send) + ptr;
const uint8_t selectedSerialPort_bak = selectedSerialPort;
@ -138,11 +136,17 @@ uint8_t optiboot_w25x20cl_enter()
ptr = entry_magic_receive;
end = strlen_P(entry_magic_receive) + ptr;
while (ptr != end) {
while (rx_buffer.head == SerialHead) {
unsigned long boot_timer = 2000000;
// Beware of this volatile pointer - it is important since the while-cycle below
// doesn't contain any obvious references to rx_buffer.head
// thus the compiler is allowed to remove the check from the cycle
// i.e. rx_buffer.head == SerialHead would not be checked at all!
// With the volatile keyword the compiler generates exactly the same code as without it with only one difference:
// the last brne instruction jumps onto the (*rx_head == SerialHead) check and NOT onto the wdr instruction bypassing the check.
volatile int *rx_head = &rx_buffer.head;
while (*rx_head == SerialHead) {
wdt_reset();
delayMicroseconds(1);
if (++ boot_timer > boot_timeout)
{
if ( --boot_timer == 0) {
// Timeout expired, continue with the application.
selectedSerialPort = selectedSerialPort_bak; //revert Serial setting
return 0;
@ -161,6 +165,7 @@ uint8_t optiboot_w25x20cl_enter()
cbi(UCSR0B, RXCIE0); //disable the MarlinSerial0 interrupt
// Send the cfm magic string.
ptr = entry_magic_cfm;
end = strlen_P(entry_magic_cfm) + ptr;
while (ptr != end)
putch(pgm_read_byte(ptr ++));
}