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Enhancement
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Resolution: Implemented
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Low
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Code Generation Tools
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CODEGEN-7111
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MSP430_18.12.2.LTS
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MSP430_20.2.0.LTS*
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default
The attached test has this line ...
return a | __swap_bytes(b);
a and b are of type unsigned char. Build it with optimization ...
% cl430 -vmspx -o -s try1.c
... and the resulting assembly is not very good.
;** 7 ----------------------- return (unsigned)a|(unsigned)b>>8|(unsigned)b<<8;
.dwpsn file "try1.c",line 7,column 5,is_stmt,isa 0
MOV.B &a+0,r15 ; [] |7|
MOV.B &b+0,r12 ; [] |7|
SWPB r12 ; [] |7|
MOV.B r12,r12 ; [] |7|
OR.W r12,r15 ; [] |7|
MOV.B &b+0,r12 ; [] |7|
RPT #8 || RLAX.W r12 ; [] |7|
OR.W r15,r12 ; [] |7|
Build it with no optimization ...
% cl430 -vmspx -ooff -s try1.c
... and the resulting assembly is much better ...
;----------------------------------------------------------------------
; 7 | return a | __swap_bytes(b);
;----------------------------------------------------------------------
MOV.B &a+0,r15 ; [] |7|
MOV.B &b+0,r12 ; [] |7|
SWPB r12 ; [] |7|
OR.W r15,r12 ; [] |7|
