Data Types | CS+ V4.01.00

5.6.6 Data Types

The RX CPU can handle four types of data: integer, floating-point, bit, and string.

(1)

Integer

An integer can be signed or unsigned. For signed integers, negative values are represented by two's complements.

Figure 5.3

Integer Data

(2)	Floating-Point

Floating-point support is for the single-precision floating-point type specified in IEEE754; operands of this type can be used in eight floating-point operation instructions: FADD, FCMP, FDIV, FMUL, FSUB, FTOI, ITOF, and ROUND.

Note

Since products of the RX200 Series do not support instructions for floating-point operations, the floating-point exception does not occur.

The floating-point format supports the values listed below.
0 < E < 255 (normal numbers)
E = 0 and F = 0 (signed zero)
E = 0 and F > 0 (denormalized numbers)*
E = 255 and F = 0 (infinity)
E = 255 and F > 0 (NaN: Not-a-Number)

Note	* The number is treated as 0 when the DN bit in the FPSW is 1. When the DN bit is 0, an unimplemented processing exception is generated.

Figure 5.4

Floating-point Data

(3)	Bitwise Operations

Five bit-manipulation instructions are provided for bitwise operations: BCLR, BMCnd, BNOT, BSET, and BTST.

A bit in a register is specified as the destination register and a bit number in the range from 31 to 0.

A bit in memory is specified as the destination address and a bit number from 7 to 0. The addressing modes available to specify addresses are register indirect and register relative.

Figure 5.5

(4)

Strings

The string data type consists of an arbitrary number of consecutive byte (8-bit), word (16-bit), or longword (32-bit) units. Seven string manipulation instructions are provided for use with strings: SCMPU, SMOVB, SMOVF, SMOVU, SSTR, SUNTIL, and SWHILE.

Figure 5.6

String Data