Dmitry, I posted a suggestion for optimization a week ago. This seems to be a good candidate for the peephole optimizer. See original post below.
Ralf ----------------------- "Ralf Guetlein" <ralf.guetl...@web.de> schrieb im Newsbeitrag news:bh819s$5v...@sea.gmane.org... > Hi all, > > as you see in the disassembly listing below, there is > a small lack of optimisation: > > The compiler refuses to use autoincrement when moving > byte blocks. With integer values it works ok. > > move bytes: > 6: ee 4f 00 00 mov.b @r15, 0(r14) ; > a: 1f 53 inc r15 ; > c: 1e 53 inc r14 ; > > move integers: > 1c: be 4f 00 00 mov @r15+, 0(r14) ; > 20: 2e 53 incd r14 ; > > I assume this can be fixed easily, but I'm not too much > involved in gcc programming now, so I ask for your support. > > Regards, > Ralf > > See the whole listing below: > > > > test.o: file format elf32-msp430 > > Disassembly of section .text: > > 00000000 <copybytes>: > void copybytes(char *src, char *dst, int len) > { > while (len--) > 0: 3d 53 add #-1, r13 ;r3 As==11 > 2: 3d 93 cmp #-1, r13 ;r3 As==11 > 4: 07 24 jz $+16 ;abs 0x14 > *dst++ = *src++; > 6: ee 4f 00 00 mov.b @r15, 0(r14) ; > a: 1f 53 inc r15 ; > c: 1e 53 inc r14 ; > e: 3d 53 add #-1, r13 ;r3 As==11 > 10: 3d 93 cmp #-1, r13 ;r3 As==11 > 12: f9 23 jnz $-12 ;abs 0x6 > } > 14: 30 41 ret > > 00000016 <copywords>: > > > void copywords(int *src, int *dst, int len) > { > while (len--) > 16: 3d 53 add #-1, r13 ;r3 As==11 > 18: 3d 93 cmp #-1, r13 ;r3 As==11 > 1a: 06 24 jz $+14 ;abs 0x28 > *dst++ = *src++; > 1c: be 4f 00 00 mov @r15+, 0(r14) ; > 20: 2e 53 incd r14 ; > 22: 3d 53 add #-1, r13 ;r3 As==11 > 24: 3d 93 cmp #-1, r13 ;r3 As==11 > 26: fa 23 jnz $-10 ;abs 0x1c > } > 28: 30 41 ret >
