MEM_VAL_COPY_GET_xxx()

These macros copy and decode data values from any CPU memory address to any other memory address.

Files

lib_mem.h

Prototypes

MEM_VAL_COPY_GET_INT08U_BIG(addr_dest, addr_src);
MEM_VAL_COPY_GET_INT16U_BIG(addr_dest, addr_src);
MEM_VAL_COPY_GET_INT32U_BIG(addr_dest, addr_src);
MEM_VAL_COPY_GET_INTU_BIG(addr_dest, addr_src, val_size);

MEM_VAL_COPY_GET_INT08U_LITTLE(addr_dest, addr_src);
MEM_VAL_COPY_GET_INT16U_LITTLE(addr_dest, addr_src);
MEM_VAL_COPY_GET_INT32U_LITTLE(addr_dest, addr_src);
MEM_VAL_COPY_GET_INTU_LITTLE(addr_dest, addr_src, val_size);

MEM_VAL_COPY_GET_INT08U(addr_dest, addr_src);
MEM_VAL_COPY_GET_INT16U(addr_dest, addr_src);
MEM_VAL_COPY_GET_INT32U(addr_dest, addr_src);
MEM_VAL_COPY_GET_INTU(addr_dest, addr_src, val_size);

Arguments

addr_dest

Lowest CPU memory address to copy/decode source address’s data value.

addr_src

Lowest CPU memory address of the data value to copy/decode.

val_size

Number of data value octets to copy/decode.

Returned Value

None.

Required Configuration

None.

Notes / Warnings

CPU memory addresses/pointers not checked for NULL nor overlapping memory addresses which may result in undefined copy behavior.

Copy/decode data values based on the values’ data-word order in CPU memory:

MEM_VAL_COPY_GET_xxx_BIG()

Decode big-endian data values — data words’ most significant octet at lowest memory address

MEM_VAL_COPY_GET_xxx_LITTLE()

Decode little-endian data values — data words’ least significant octet at lowest memory address

MEM_VAL_COPY_GET_xxx()

Decode data values using CPU’s native or configured data-word order

MEM_VAL_COPY_GET_xxx() macros copy/decode data values without regard to CPU word-aligned addresses. Thus for processors that require data word alignment, data words can be copied/decoded to/from any CPU addresses, word-aligned or not, without generating data-word-alignment exceptions/faults.

MEM_VAL_COPY_GET_xxx() macros are more efficient than MEM_VAL_GET_xxx() macros and are also fully independent of CPU data-word-alignment and should be used whenever possible. Fixed-size copy MEM_VAL_COPY_GET_INTxxU_xxx() macros are more efficient than dynamic-size copy MEM_VAL_COPY_GET_INTU_xxx() macros and should be used whenever possible.

MEM_VAL_COPY_GET_xxx() macros are not atomic operations and must not be used on any non-static (i.e., volatile) variables, registers, hardware, etc.; without the caller of the macros providing some form of additional protection (e.g. mutual exclusion).

Since octet-order copy/conversion are inverse operations, MEM_VAL_COPY_GET_xxx() and MEM_VAL_COPY_SET_xxx() memory data-copy get/set macros are inverse, but identical, operations and are provided in both forms for semantics and consistency.

Example Usage

          CPU_INT16U  *pmem;
          CPU_INT16U  *pval;
          CPU_INT08U   buf[SIZE];
           
          pmem = &SomeAddr;                    /* Any CPU address */
          pval = &SomeVal;                     /* Any CPU address */
          MEM_VAL_COPY_GET_INT16U(pmem, pval);
          MEM_VAL_COPY_GET_INTU(&buf[0], pmem, sizeof(buf));