ARM Technical Support Knowledge Articles

INCREMENTING HUGE POINTER ONLY CHANGES LOWER 16-BITS

Applies to: C166 C Compiler

Answer


Information in this article applies to:


SYMPTOMS

I am trying to compute the CRC of a 96Kb area in flash memory. Doing this involves incrementing a pointer which is passed as a function argument, defined as

crc_16h(unsigned char huge* p, len);

The C166 compiler increments only the lower 16 bits of the pointer p, which gives the wrong result. Is this fixed in a later version?

CAUSE

The huge memory type only supports 16-bit address calculation. This means that only the lower 16-bits of a pointer may be used to calculate addresses. The result is that the huge memory type can only access objects up to 64Kb in size.

RESOLUTION

Change your pointer to the xhuge memory type. xhuge supports full 32-bit address calculation and can access objects with 'unlimited' size.

MORE INFORMATION

Article last edited on: 2005-07-15 13:00:31

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