DEF_BITxx()

Creates a bit mask based on a single bit-number position.

Files

lib_def.h

Prototypes

          DEF_BIT(bit);
           
          DEF_BIT08(bit);
          DEF_BIT16(bit);
          DEF_BIT32(bit);
          DEF_BIT64(bit);

Arguments

bit

Bit number of the bit mask to set.

Returned Value

Bit mask with the single bit number position set.

Required Configuration

None.

Notes / Warnings

bit should be a non-negative integer.

bit values that overflow the target CPU and/or compiler environment (e.g. negative or greater-than-CPU-data-size values) may generate compiler warnings and/or errors.

To avoid overflowing any target CPU and/or compiler’s integer data type, unsigned bit constant 1 is either cast to specified integer data type size or suffixed with long integer modifier, ‘L’. This may still be insufficient for CPUs and/or compilers that support long long integer data types, in which case ‘LL’ integer modifier should be suffixed. However, since almost all 16- and 32-bit CPUs and compilers support long integer data types but many may not support long long integer data types, only long integer data types and modifiers are supported.

Example Usage

          CPU_INT16U  mask_16;
          CPU_INT32U  mask_32;
           
          mask_16 = DEF_BIT(12u);
          mask_16 = DEF_BIT16(15u);
          mask_32 = DEF_BIT(19u);
          mask_32 = DEF_BIT16(23u);   /* 16-bit shift macro overflows; sets mask_32 = 0          */
          mask_32 = DEF_BIT32(28u);   /* 32-bit shift macro correctly  sets mask_32 = 0x10000000 */