8XC196MC, MD, MH USER’S MANUAL

Table 3-2 lists the equivalent operand-type names for both C programming and assembly lan- guage.

Table 3-2. Equivalent Operand Types for Assembly and C Programming Languages

Operand Types

Assembly Language Equivalent

C Programming Language Equivalent

 

 

 

BYTE

BYTE

unsigned char

 

 

 

SHORT-INTEGER

BYTE

char

 

 

 

WORD

WORD

unsigned int

 

 

 

INTEGER

WORD

int

 

 

 

DOUBLE-WORD

LONG

unsigned long

 

 

 

LONG-INTEGER

LONG

long

 

 

 

3.1.1BIT Operands

A BIT is a single-bit variable that can have the Boolean values, “true” and “false.” The architec- ture requires that BITs be addressed as components of BYTEs or WORDs. It does not support the direct addressing of BITs.

3.1.2BYTE Operands

ABYTE is an unsigned, 8-bit variable that can take on values from 0 through 255 (28–1). Arith- metic and relational operators can be applied to BYTE operands, but the result must be interpret- ed in modulo 256 arithmetic. Logical operations on BYTEs are applied bitwise. Bits within BYTEs are labeled from 0 to 7; bit 0 is the least-significant bit. There are no alignment restric- tions for BYTEs, so they may be placed anywhere in the address space.

3.1.3SHORT-INTEGER Operands

A SHORT-INTEGER is an 8-bit, signed variable that can take on values from –128 (–2 7) through +127 (+27–1). Arithmetic operations that generate results outside the range of a SHORT- INTEGER set the overflow flags in the processor status word (PSW). The numeric result is the same as the result of the equivalent operation on BYTE variables. There are no alignment restric- tions on SHORT-INTEGERs, so they may be placed anywhere in the address space.

3.1.4WORD Operands

AWORD is an unsigned, 16-bit variable that can take on values from 0 through 65,535 (216–1). Arithmetic and relational operators can be applied to WORD operands, but the result must be in- terpreted in modulo 65536 arithmetic. Logical operations on WORDs are applied bitwise. Bits within WORDs are labeled from 0 to 15; bit 0 is the least-significant bit.

3-2

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Intel 8XC196MC, 8XC196MD, 8XC196MH manual BIT Operands, Byte Operands, SHORT-INTEGER Operands, Word Operands