URL:
<http://savannah.nongnu.org/bugs/?43828>
Summary: wdt.h: Wrong inline assembler arguments
Project: AVR C Runtime Library
Submitted by: gjlayde
Submitted on: Mo 15 Dez 2014 19:25:34 GMT
Category: Header
Severity: 3 - Normal
Priority: 5 - Normal
Item Group: Header files
Status: None
Percent Complete: 0%
Assigned to: None
Originator Email:
Open/Closed: Open
Discussion Lock: Any
Release: 1.8.0
Fixed Release: None
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Details:
wdt.h comes with wrong inline assembler arguments. Let me give an example
(2014-12-15 SVN trunk r2641):
#define wdt_enable(timeout) \
do { \
uint8_t temp = 0; \
__asm__ __volatile__ ( \
"in __tmp_reg__, %[rampd]" "\n\t" \
"out %[rampd], __zero_reg__" "\n\t" \
"out %[ccp_reg], %[ioreg_cen_mask]" "\n\t" \
"sts %[wdt_reg], %[wdt_enable_timeout]" "\n\t" \
"1:lds %[tmp], %[wdt_status_reg]" "\n\t" \
"sbrc %[tmp], %[wdt_syncbusy_bit]" "\n\t" \
"rjmp 1b" "\n\t" \
"out %[rampd], __tmp_reg__" "\n\t" \
: "=r" (temp) \
: [rampd] "M" (_SFR_MEM_ADDR(RAMPD)), \
[ccp_reg] "I" (_SFR_MEM_ADDR(CCP)), \
[ioreg_cen_mask] "r" ((uint8_t)CCP_IOREG_gc), \
[wdt_reg] "M" (_SFR_MEM_ADDR(WDT_CTRL)), \
[wdt_enable_timeout] "r" ((uint8_t)(WDT_CEN_bm | WDT_ENABLE_bm |
timeout)), \
[wdt_status_reg] "M" (_SFR_MEM_ADDR(WDT_STATUS)), \
[wdt_syncbusy_bit] "I" (WDT_SYNCBUSY_bm), \
[tmp] "r" (temp) \
: "r0" \
); \
} while(0)
Operand %[tmp] (%8) is changed but not indicated as so by means of constraint
modifiers.
Notice that the compiler may allocate different registers to %0 and %8.
Hence, the fix is to refer to %0 instead of to %[tmp] resp. moving %[tmp] to
the first operand. Also notice that %8 is unused and can be dropped. temp is
loaded with 0 but respective content of %[tmp] is discarded by LDS.
The other asm in wdt.h (or maybe even more headers or source files) might
suffer from the same or similar flaws.
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