If the processing in each case label of a switch statement is almost the same, consider the usage of a table.
[Example]
The character constant to be assigned to variable ch is changed by the value of variable i.
Source code before improvement
char func(int i)
{
char ch;
switch (i) {
case 0:
ch = ’a'; break;
case 1:
ch = ’x'; break;
case 2:
ch = ’b'; break;
}
return(ch);
}
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Assembly-language expansion code before improvement
_func:
CMP #00H,R1
BEQ L17
L16:
CMP #01H,R1
BEQ L19
CMP #02H,R1
BEQ L20
BRA L21
L12:
L17:
MOV.L #00000061H,R1
BRA L21
L13:
L19:
MOV.L #00000078H,R1
BRA L21
L14:
L20:
MOV.L #00000062H,R1
L11:
L21:
MOVU.B R1,R1
RTS
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Source code after improvement
char chbuf[] = {'a', 'x', 'b'};
char func(int i)
{
return (chbuf[i]);
}
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Assembly-language expansion code after improvement
_f
MOV.L #_chbuf,R4
MOVU.B [R1,R4],R1
RTS
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