UNSIGNED_CHAR Compiler Directive

Abbreviation

UCH

Arguments

None.

Default

Variables of type char are signed.

µVision

Options — C251 — Treat 'char' as 'unsigned char'.

Description

The UNSIGNED_CHAR directive instructs the compiler to treat all variables declared with char as unsigned char variables.

Example

C251 SAMPLE.C UNSIGNED_CHAR

#pragma UCH

The following example:

 stmt lvl     source
    1         char  ch1;
    2         unsigned char uch2;   /* always unsigned */
    3         signed char sch3;     /* always signed   */
    4
    5         int i;
    6
    7         void test (void)  {
    8  1        if (ch1  > 0) i = ch1;
    9  1        if (uch2 > 0) i = uch2;
   10  1        if (sch3 > 0) i = sch3;
   11  1      }

demonstrates code generated using the SIGNED_CHAR directive:

Code Generated
Without UNSIGNED_CHAR

; FUNCTION uchar (BEGIN  RMASK = @0x0030)
                   ; SOURCE LINE # 7
                   ; SOURCE LINE # 8
0000 F3FA0200 R    MOVB      RL5,ch1
0004 49A0          CMPB      RL5,#00H
0006 BD03          JMPR      cc_SLE,?C0001
0008 D0A4          MOVBS     R4,RL5
000A F6F40000 R    MOV       i,R4
000E         ?C0001:
                   ; SOURCE LINE # 9
000E F3FA0300 R    MOVB      RL5,uch2
0012 49A0          CMPB      RL5,#00H
0014 FD03          JMPR      cc_ULE,?C0002
0016 C0A4          MOVBZ     R4,RL5
0018 F6F40000 R    MOV       i,R4
001C         ?C0002:
                   ; SOURCE LINE # 10
001C F3FA0400 R    MOVB      RL5,sch3
0020 49A0          CMPB      RL5,#00H
0022 BD03          JMPR      cc_SLE,?C0003
0024 D0A4          MOVBS     R4,RL5
0026 F6F40000 R    MOV       i,R4
002A         ?C0003:
                   ; SOURCE LINE # 11
002A CB00          RET
; FUNCTION uchar (END    RMASK = @0x0030)

CODE SIZE: 44 Bytes

Code Generated
With UNSIGNED_CHAR

; FUNCTION uchar (BEGIN  RMASK = @0x0030)
                   ; SOURCE LINE # 7
                   ; SOURCE LINE # 8
0000 F3FA0200 R    MOVB      RL5,ch1
0004 49A0          CMPB      RL5,#00H
0006 FD03          JMPR      cc_ULE,?C0001
0008 C0A4          MOVBZ     R4,RL5
000A F6F40000 R    MOV       i,R4
000E         ?C0001:
                   ; SOURCE LINE # 9
000E F3FA0300 R    MOVB      RL5,uch2
0012 49A0          CMPB      RL5,#00H
0014 FD03          JMPR      cc_ULE,?C0002
0016 C0A4          MOVBZ     R4,RL5
0018 F6F40000 R    MOV       i,R4
001C         ?C0002:
                   ; SOURCE LINE # 10
001C F3FA0400 R    MOVB      RL5,sch3
0020 49A0          CMPB      RL5,#00H
0022 BD03          JMPR      cc_SLE,?C0003
0024 D0A4          MOVBS     R4,RL5
0026 F6F40000 R    MOV       i,R4
002A         ?C0003:
                   ; SOURCE LINE # 11
002A CB00          RET
; FUNCTION uchar (END    RMASK = @0x0030)

CODE SIZE: 44 Bytes

UNSIGNED_CHAR Compiler Directive

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