SW500010 Microchip Technology, SW500010 Datasheet - Page 94

• Manufacturer Part Number: SW500010
• Description: HI-TECH C PRO FOR PIC10/12/16
• Manufacturer: Microchip Technology
• Type: Compilerr
• Series: PIC10/12/16r

Specifications of SW500010

• Supported Families: PIC10, PIC12, PIC16
• Core Architecture: PIC
• Software Edition: Professional
• Kit Contents: Software And Docs
• Mcu Supported Families: PIC10/12/16
• Tool Type: Compiler
• Lead Free Status / RoHS Status: Not applicable / Not applicable
• For Use With/related Products: PIC10, PIC12, PIC14, PIC16, PIC16E
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 019P; 778-1006; 778-1006

Operators
operator toggles each bit within a value. Consider the following code.
c = 0x55;
if( ~c == 0xAA)
count++;
FFAAh and so the comparison in the above example would fail. The compiler may be able to issue
a mismatched comparison error to this effect in some circumstances. Again, a cast could be used to
change this behaviour.
with char-type operands, but with int-type operands. However there are circumstances when the
result of an operation is identical regardless of whether the operands are of type char or int. In
these cases, HI-TECH C will not perform the integral promotion so as to increase the code efficiency.
Consider the following example.
a = b + c;
unsigned int, the addition performed, the result of the addition cast to the type of a, and then
the assignment can take place. Even if the result of the unsigned int addition of the promoted
values of b and c was different to the result of the unsigned char addition of these values with-
out promotion, after the unsigned int result was converted back to unsigned char, the final
result would be the same. If an 8-bit addition is more efficient than a 16-bit addition, the compiler
will encode the former.
have to be performed to comply with the ANSI standard.
3.7.2 Shifts applied to integral types
The ANSI standard states that the result of right shifting (> > operator) signed integral types is
implementation defined when the operand is negative. Typically, the possible actions that can be
taken are that when an object is shifted right by one bit, the bit value shifted into the most significant
bit of the result can either be zero, or a copy of the most significant bit before the shift took place.
The latter case amounts to a sign extension of the number.
integral type (for example signed char, signed int or signed long). Thus an object with
the signed int value 0x0124 shifted right one bit will yield the value 0x0092 and the value
0x8024 shifted right one bit will yield the value 0xC012.
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Another problem that frequently occurs is with the bitwise compliment operator, “~”. This
unsigned char count, c;
If c contains the value 55h, it often assumed that ~c will produce AAh, however the result is
The consequence of integral promotion as illustrated above is that operations are not performed
unsigned char a, b, c;
Strictly speaking, this statement requires that the values of b and c should be promoted to
If, in the above example, the type of a was unsigned int, then integral promotion would
HI-TECH C PRO for the PIC10/12/16 MCU Family performs a sign extension of any signed
Right shifts of unsigned integral values always clear the most significant bit of the result.
C Language Features