RealView Compilation Tools Compiler Reference Guide - ARM ...

Compiler-specific Features
Where:
ptr
Points to the address of the data to be loaded from memory. To specify
the size of the data to be loaded, cast the parameter to an appropriate
integral type.
Table 4-9 Access widths supported by the __ldrt intrinsic
Instruction a
Size of data loaded
C cast
LDRSBT signed byte (signed char *)
LDRBT unsigned byte (char *)
LDRSHT signed half word (signed short int *)
LDRHT unsigned halfword (short int *)
LDRT word (int *)
a. Or equivalent.
Return value
The __ldrt intrinsic returns the data loaded from the memory address pointed to by ptr.
Errors
The compiler does not recognize the __ldrt intrinsic when compiling for a target that
does not support the LDRT instruction. The compiler generates either a warning or an
error in this case.
The __ldrt intrinsic does not support access to doubleword data. The compiler
generates an error if you specify an access width that is not supported.
Example
int foo(void)
{
int loc = 0xff;
return __ldrt((const volatile int *)loc);
}
Compiling this code with the default options produces:
||foo|| PROC
MOV
LDRBT
r0,#0xff
r1,[r0],#0
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