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| author | kriegsman@gmail.com <kriegsman@gmail.com@4ad4ec5c-605d-bd5c-5796-512c9b60011b> | 2013-05-10 06:11:30 +0400 |
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| committer | kriegsman@gmail.com <kriegsman@gmail.com@4ad4ec5c-605d-bd5c-5796-512c9b60011b> | 2013-05-10 06:11:30 +0400 |
| commit | 2bfc63e5ad10459d5faf70fda49e52177fcbbd41 (patch) | |
| tree | ba695ea754f9dd592dd031fb102e58f162b06c55 /lib8tion.cpp | |
| parent | 04e31d2959649a4ec7c8f5b8d6e62fd47972847e (diff) | |
MEK: linear interpolations (lerps), scaling, and an easing function.In this episode, we learn that avr-gcc will generate a fast inline bit-shift for uint32_t / 256, but a call to an external long division routine for signed int32_t / 256. I believe the term of art for this is 'missed optimization'.
Diffstat (limited to 'lib8tion.cpp')
| -rw-r--r-- | lib8tion.cpp | 122 |
1 files changed, 61 insertions, 61 deletions
diff --git a/lib8tion.cpp b/lib8tion.cpp index ffe4bd0b..224d44f2 100644 --- a/lib8tion.cpp +++ b/lib8tion.cpp @@ -25,27 +25,27 @@ uint16_t rand16seed = RAND16_SEED; #if defined(__AVR__) extern "C" { //__attribute__ ((noinline)) -void * memset8 ( void * ptr, int val, uint16_t num ) +void * memset8 ( void * ptr, uint8_t val, uint16_t num ) { asm volatile( - " movw r26, %[ptr] \n\t" - " sbrs %A[num], 0 \n\t" - " rjmp Lseteven_%= \n\t" - " rjmp Lsetodd_%= \n\t" - "Lsetloop_%=: \n\t" - " st X+, %A[val] \n\t" - "Lsetodd_%=: \n\t" - " st X+, %A[val] \n\t" - "Lseteven_%=: \n\t" - " subi %A[num], 2 \n\t" - " brcc Lsetloop_%= \n\t" - " sbci %B[num], 0 \n\t" - " brcc Lsetloop_%= \n\t" - : [num] "+r" (num) - : [ptr] "r" (ptr), - [val] "r" (val) - : "memory" - ); + " movw r26, %[ptr] \n\t" + " sbrs %A[num], 0 \n\t" + " rjmp Lseteven_%= \n\t" + " rjmp Lsetodd_%= \n\t" + "Lsetloop_%=: \n\t" + " st X+, %[val] \n\t" + "Lsetodd_%=: \n\t" + " st X+, %[val] \n\t" + "Lseteven_%=: \n\t" + " subi %A[num], 2 \n\t" + " brcc Lsetloop_%= \n\t" + " sbci %B[num], 0 \n\t" + " brcc Lsetloop_%= \n\t" + : [num] "+r" (num) + : [ptr] "r" (ptr), + [val] "r" (val) + : "memory" + ); return ptr; } @@ -55,27 +55,27 @@ void * memset8 ( void * ptr, int val, uint16_t num ) void * memcpy8 ( void * dst, void* src, uint16_t num ) { asm volatile( - " movw r30, %[src] \n\t" - " movw r26, %[dst] \n\t" - " sbrs %A[num], 0 \n\t" - " rjmp Lcpyeven_%= \n\t" - " rjmp Lcpyodd_%= \n\t" - "Lcpyloop_%=: \n\t" - " ld __tmp_reg__, Z+ \n\t" - " st X+, __tmp_reg__ \n\t" - "Lcpyodd_%=: \n\t" - " ld __tmp_reg__, Z+ \n\t" - " st X+, __tmp_reg__ \n\t" - "Lcpyeven_%=: \n\t" - " subi %A[num], 2 \n\t" - " brcc Lcpyloop_%= \n\t" - " sbci %B[num], 0 \n\t" - " brcc Lcpyloop_%= \n\t" - : [num] "+r" (num) - : [src] "r" (src), - [dst] "r" (dst) - : "memory" - ); + " movw r30, %[src] \n\t" + " movw r26, %[dst] \n\t" + " sbrs %A[num], 0 \n\t" + " rjmp Lcpyeven_%= \n\t" + " rjmp Lcpyodd_%= \n\t" + "Lcpyloop_%=: \n\t" + " ld __tmp_reg__, Z+ \n\t" + " st X+, __tmp_reg__ \n\t" + "Lcpyodd_%=: \n\t" + " ld __tmp_reg__, Z+ \n\t" + " st X+, __tmp_reg__ \n\t" + "Lcpyeven_%=: \n\t" + " subi %A[num], 2 \n\t" + " brcc Lcpyloop_%= \n\t" + " sbci %B[num], 0 \n\t" + " brcc Lcpyloop_%= \n\t" + : [num] "+r" (num) + : [src] "r" (src), + [dst] "r" (dst) + : "memory" + ); return dst; } @@ -90,27 +90,27 @@ void * memmove8 ( void * dst, void* src, uint16_t num ) dst = (char*)dst + num; src = (char*)src + num; asm volatile( - " movw r30, %[src] \n\t" - " movw r26, %[dst] \n\t" - " sbrs %A[num], 0 \n\t" - " rjmp Lmoveven_%= \n\t" - " rjmp Lmovodd_%= \n\t" - "Lmovloop_%=: \n\t" - " ld __tmp_reg__, -Z \n\t" - " st -X, __tmp_reg__ \n\t" - "Lmovodd_%=: \n\t" - " ld __tmp_reg__, -Z \n\t" - " st -X, __tmp_reg__ \n\t" - "Lmoveven_%=: \n\t" - " subi %A[num], 2 \n\t" - " brcc Lmovloop_%= \n\t" - " sbci %B[num], 0 \n\t" - " brcc Lmovloop_%= \n\t" - : [num] "+r" (num) - : [src] "r" (src), - [dst] "r" (dst) - : "memory" - ); + " movw r30, %[src] \n\t" + " movw r26, %[dst] \n\t" + " sbrs %A[num], 0 \n\t" + " rjmp Lmoveven_%= \n\t" + " rjmp Lmovodd_%= \n\t" + "Lmovloop_%=: \n\t" + " ld __tmp_reg__, -Z \n\t" + " st -X, __tmp_reg__ \n\t" + "Lmovodd_%=: \n\t" + " ld __tmp_reg__, -Z \n\t" + " st -X, __tmp_reg__ \n\t" + "Lmoveven_%=: \n\t" + " subi %A[num], 2 \n\t" + " brcc Lmovloop_%= \n\t" + " sbci %B[num], 0 \n\t" + " brcc Lmovloop_%= \n\t" + : [num] "+r" (num) + : [src] "r" (src), + [dst] "r" (dst) + : "memory" + ); return dst; } } |