Mixer: Rework for performance, particularly of the S16 case
This removes downscaling (halving-add) when multiple voices are being mixed. To avoid clipping, and get similar behavior to before, set the "level" of each voice to (1/voice_count). Slow paths that were applicable to only M0 chips were removed. As a side effect, the internal volume representation is now 0 .. 0x8000 (inclusive), which additionally makes a level of exactly 0.5 representable. Testing performed, on PyGamer: For all 4 data cases, for stereo and mono, for 1 and 2 voices, play pure sign waves represented as RawSamples and view the result on a scope and through headphones. Also, scope the amount of time spent in background tasks. Code size: growth of +272 bytes Performance (time in background task when mixing 2 stereo 16-bit voices): 76us per down from 135us (once per ~2.9ms long term average) (Decrease from 4.7% to 2.4% of all CPU time)
This commit is contained in:
Jeff Epler
parent
e6869c8983
commit
449dbea456
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@ -101,213 +101,60 @@ void audiomixer_mixer_reset_buffer(audiomixer_mixer_obj_t* self,
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}
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}
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uint32_t add8signed(uint32_t a, uint32_t b) {
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#if (defined (__ARM_ARCH_7EM__) && (__ARM_ARCH_7EM__ == 1)) //Cortex-M4 w/FPU
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return __SHADD8(a, b);
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#else
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uint32_t result = 0;
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for (int8_t i = 0; i < 4; i++) {
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int8_t ai = a >> (sizeof(int8_t) * 8 * i);
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int8_t bi = b >> (sizeof(int8_t) * 8 * i);
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int32_t intermediate = (int32_t) ai + bi / 2;
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if (intermediate > CHAR_MAX) {
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intermediate = CHAR_MAX;
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} else if (intermediate < CHAR_MIN) {
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intermediate = CHAR_MIN;
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}
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result |= ((uint32_t) intermediate & 0xff) << (sizeof(int8_t) * 8 * i);
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}
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return result;
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#endif
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}
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uint32_t add8unsigned(uint32_t a, uint32_t b) {
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#if (defined (__ARM_ARCH_7EM__) && (__ARM_ARCH_7EM__ == 1)) //Cortex-M4 w/FPU
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return __UHADD8(a, b);
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#else
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uint32_t result = 0;
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for (int8_t i = 0; i < 4; i++) {
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uint8_t ai = (a >> (sizeof(uint8_t) * 8 * i));
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uint8_t bi = (b >> (sizeof(uint8_t) * 8 * i));
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int32_t intermediate = (int32_t) (ai + bi) / 2;
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if (intermediate > UCHAR_MAX) {
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intermediate = UCHAR_MAX;
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}
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result |= ((uint32_t) intermediate & 0xff) << (sizeof(uint8_t) * 8 * i);
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}
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return result;
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#endif
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}
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uint32_t add16signed(uint32_t a, uint32_t b) {
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#if (defined (__ARM_ARCH_7EM__) && (__ARM_ARCH_7EM__ == 1)) //Cortex-M4 w/FPU
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return __SHADD16(a, b);
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#else
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uint32_t result = 0;
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for (int8_t i = 0; i < 2; i++) {
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int16_t ai = a >> (sizeof(int16_t) * 8 * i);
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int16_t bi = b >> (sizeof(int16_t) * 8 * i);
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int32_t intermediate = (int32_t) ai + bi / 2;
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if (intermediate > SHRT_MAX) {
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intermediate = SHRT_MAX;
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} else if (intermediate < SHRT_MIN) {
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intermediate = SHRT_MIN;
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}
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result |= (((uint32_t) intermediate) & 0xffff) << (sizeof(int16_t) * 8 * i);
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}
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return result;
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#endif
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}
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uint32_t add16unsigned(uint32_t a, uint32_t b) {
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#if (defined (__ARM_ARCH_7EM__) && (__ARM_ARCH_7EM__ == 1)) //Cortex-M4 w/FPU
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return __UHADD16(a, b);
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#else
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uint32_t result = 0;
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for (int8_t i = 0; i < 2; i++) {
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int16_t ai = (a >> (sizeof(uint16_t) * 8 * i)) - 0x8000;
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int16_t bi = (b >> (sizeof(uint16_t) * 8 * i)) - 0x8000;
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int32_t intermediate = (int32_t) ai + bi / 2;
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if (intermediate > USHRT_MAX) {
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intermediate = USHRT_MAX;
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}
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result |= ((uint32_t) intermediate & 0xffff) << (sizeof(int16_t) * 8 * i);
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}
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return result;
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#endif
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}
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static inline uint32_t mult8unsigned(uint32_t val, int32_t mul) {
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// if mul == 0, no need in wasting cycles
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if (mul == 0) {
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return 0;
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}
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/* TODO: workout ARMv7 instructions
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#if (defined (__ARM_ARCH_7EM__) && (__ARM_ARCH_7EM__ == 1)) //Cortex-M4 w/FPU
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return val;
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#else*/
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uint32_t result = 0;
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float mod_mul = (float) mul / (float) ((1<<15)-1);
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for (int8_t i = 0; i < 4; i++) {
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uint8_t ai = val >> (sizeof(uint8_t) * 8 * i);
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int32_t intermediate = ai * mod_mul;
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if (intermediate > SHRT_MAX) {
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intermediate = SHRT_MAX;
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}
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result |= ((uint32_t) intermediate & 0xff) << (sizeof(uint8_t) * 8 * i);
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}
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return result;
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//#endif
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}
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static inline uint32_t mult8signed(uint32_t val, int32_t mul) {
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// if mul == 0, no need in wasting cycles
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if (mul == 0) {
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return 0;
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}
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/* TODO: workout ARMv7 instructions
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#if (defined (__ARM_ARCH_7EM__) && (__ARM_ARCH_7EM__ == 1)) //Cortex-M4 w/FPU
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return val;
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#else
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*/
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uint32_t result = 0;
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float mod_mul = (float)mul / (float)((1<<15)-1);
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for (int8_t i = 0; i < 4; i++) {
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int16_t ai = val >> (sizeof(int8_t) * 8 * i);
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int32_t intermediate = ai * mod_mul;
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if (intermediate > CHAR_MAX) {
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intermediate = CHAR_MAX;
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} else if (intermediate < CHAR_MIN) {
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intermediate = CHAR_MIN;
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}
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result |= (((uint32_t) intermediate) & 0xff) << (sizeof(int16_t) * 8 * i);
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}
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return result;
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//#endif
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}
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//TODO:
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static inline uint32_t mult16unsigned(uint32_t val, int32_t mul) {
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// if mul == 0, no need in wasting cycles
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if (mul == 0) {
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return 0;
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}
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/* TODO: the below ARMv7m instructions "work", but the amplitude is much higher/louder
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#if (defined (__ARM_ARCH_7EM__) && (__ARM_ARCH_7EM__ == 1)) //Cortex-M4 w/FPU
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// there is no unsigned equivalent to the 'SMULWx' ARMv7 Thumb function,
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// so we have to do it by hand.
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uint32_t lo = val & 0xffff;
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uint32_t hi = val >> 16;
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//mp_printf(&mp_plat_print, "pre-asm: (mul: %d)\n\tval: %x\tlo: %x\thi: %x\n", mul, val, lo, hi);
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uint32_t val_lo;
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asm volatile("mul %0, %1, %2" : "=r" (val_lo) : "r" (mul), "r" (lo));
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asm volatile("mla %0, %1, %2, %3" : "=r" (val) : "r" (mul), "r" (hi), "r" (val_lo));
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//mp_printf(&mp_plat_print, "post-asm:\n\tval: %x\tlo: %x\n\n", val, val_lo);
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return val;
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#else
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*/
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uint32_t result = 0;
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float mod_mul = (float)mul / (float)((1<<15)-1);
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for (int8_t i = 0; i < 2; i++) {
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int16_t ai = (val >> (sizeof(uint16_t) * 8 * i)) - 0x8000;
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int32_t intermediate = ai * mod_mul;
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if (intermediate > SHRT_MAX) {
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intermediate = SHRT_MAX;
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} else if (intermediate < SHRT_MIN) {
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intermediate = SHRT_MIN;
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}
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result |= (((uint32_t) intermediate) + 0x8000) << (sizeof(int16_t) * 8 * i);
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}
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return result;
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//#endif
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__attribute__((always_inline))
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static inline uint32_t add16signed(uint32_t a, uint32_t b) {
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return __QADD16(a, b);
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}
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__attribute__((always_inline))
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static inline uint32_t mult16signed(uint32_t val, int32_t mul) {
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// if mul == 0, no need in wasting cycles
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if (mul == 0) {
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return 0;
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}
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#if (defined (__ARM_ARCH_7EM__) && (__ARM_ARCH_7EM__ == 1)) //Cortex-M4 w/FPU
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mul <<= 16;
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int32_t hi, lo;
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enum { bits = 16 }; // saturate to 16 bits
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enum { shift = 0 }; // shift is done automatically
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enum { shift = 15 }; // shift is done automatically
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asm volatile("smulwb %0, %1, %2" : "=r" (lo) : "r" (mul), "r" (val));
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asm volatile("smulwt %0, %1, %2" : "=r" (hi) : "r" (mul), "r" (val));
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asm volatile("ssat %0, %1, %2, asr %3" : "=r" (lo) : "I" (bits), "r" (lo), "I" (shift));
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asm volatile("ssat %0, %1, %2, asr %3" : "=r" (hi) : "I" (bits), "r" (hi), "I" (shift));
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asm volatile("pkhbt %0, %1, %2, lsl #16" : "=r" (val) : "r" (lo), "r" (hi)); // pack
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return val;
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#else
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uint32_t result = 0;
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float mod_mul = (float)mul / (float)((1<<15)-1);
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for (int8_t i = 0; i < 2; i++) {
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int16_t ai = val >> (sizeof(int16_t) * 8 * i);
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int32_t intermediate = ai * mod_mul;
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if (intermediate > SHRT_MAX) {
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intermediate = SHRT_MAX;
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} else if (intermediate < SHRT_MIN) {
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intermediate = SHRT_MIN;
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}
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result |= (((uint32_t) intermediate) & 0xffff) << (sizeof(int16_t) * 8 * i);
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}
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return result;
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#endif
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}
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static inline uint32_t tounsigned8(uint32_t val) {
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return __UADD8(val, 0x80808080);
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}
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static inline uint32_t tounsigned16(uint32_t val) {
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return __UADD16(val, 0x80008000);
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}
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static inline uint32_t tosigned16(uint32_t val) {
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return __UADD16(val, 0x80008000);
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}
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static inline uint32_t unpack8(uint16_t val) {
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return ((val & 0xff00) << 16) | ((val & 0x00ff) << 8);
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}
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static inline uint32_t pack8(uint32_t val) {
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return ((val & 0xff000000) >> 16) | ((val & 0xff00) >> 8);
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}
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#define LIKELY(x) (__builtin_expect(!!(x), 1))
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#define UNLIKELY(x) (__builtin_expect(!!(x), 0))
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static void mix_one_voice(audiomixer_mixer_obj_t* self,
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audiomixer_mixervoice_obj_t* voice, bool voices_active,
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uint32_t* word_buffer, uint32_t length) {
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uint32_t j = 0;
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bool voice_done = voice->sample == NULL;
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for (uint32_t i = 0; i < length; i++) {
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if (!voice_done && j >= voice->buffer_length) {
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while (!voice_done && length != 0) {
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if (voice->buffer_length == 0) {
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if (!voice->more_data) {
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if (voice->loop) {
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audiosample_reset_buffer(voice->sample, false, 0);
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} else {
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voice->sample = NULL;
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voice_done = true;
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break;
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}
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}
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if (!voice_done) {
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@ -316,64 +163,81 @@ static void mix_one_voice(audiomixer_mixer_obj_t* self,
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// Track length in terms of words.
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voice->buffer_length /= sizeof(uint32_t);
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voice->more_data = result == GET_BUFFER_MORE_DATA;
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j = 0;
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}
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}
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uint32_t n = MIN(voice->buffer_length, length);
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uint32_t *src = voice->remaining_buffer;
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uint16_t level = voice->level;
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// First active voice gets copied over verbatim.
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uint32_t sample_value;
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if (voice_done) {
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// Exit early if another voice already set all samples once.
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if (voices_active) {
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continue;
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}
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sample_value = 0;
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if (!self->samples_signed) {
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if (self->bits_per_sample == 8) {
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sample_value = 0x7f7f7f7f;
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} else {
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sample_value = 0x7fff7fff;
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}
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}
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} else {
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sample_value = voice->remaining_buffer[j];
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}
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// apply the mixer level
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if (!self->samples_signed) {
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if (self->bits_per_sample == 8) {
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sample_value = mult8unsigned(sample_value, voice->level);
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} else {
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sample_value = mult16unsigned(sample_value, voice->level);
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}
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} else {
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if (self->bits_per_sample == 8) {
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sample_value = mult8signed(sample_value, voice->level);
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} else {
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sample_value = mult16signed(sample_value, voice->level);
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}
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}
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if (!voices_active) {
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word_buffer[i] = sample_value;
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} else {
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if (self->bits_per_sample == 8) {
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if (self->samples_signed) {
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word_buffer[i] = add8signed(word_buffer[i], sample_value);
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if (LIKELY(self->bits_per_sample == 16)) {
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if (LIKELY(self->samples_signed)) {
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for (uint32_t i = 0; i<n; i++) {
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uint32_t v = src[i];
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word_buffer[i] = mult16signed(v, level);
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}
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} else {
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word_buffer[i] = add8unsigned(word_buffer[i], sample_value);
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for (uint32_t i = 0; i<n; i++) {
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uint32_t v = src[i];
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v = tosigned16(v);
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word_buffer[i] = mult16signed(v, level);
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}
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}
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} else {
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if (self->samples_signed) {
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word_buffer[i] = add16signed(word_buffer[i], sample_value);
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uint16_t *hword_buffer = (uint16_t*)word_buffer;
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uint16_t *hsrc = (uint16_t*)src;
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for (uint32_t i = 0; i<n*2; i++) {
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uint32_t word = unpack8(hsrc[i]);
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if (LIKELY(!self->samples_signed)) {
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word = tosigned16(word);
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}
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word = mult16signed(word, level);
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hword_buffer[i] = pack8(word);
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}
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}
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} else {
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if (LIKELY(self->bits_per_sample == 16)) {
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if (LIKELY(self->samples_signed)) {
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for (uint32_t i = 0; i<n; i++) {
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uint32_t word = src[i];
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word_buffer[i] = add16signed(mult16signed(word, level), word_buffer[i]);
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}
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} else {
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word_buffer[i] = add16unsigned(word_buffer[i], sample_value);
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for (uint32_t i = 0; i<n; i++) {
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uint32_t word = src[i];
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word = tosigned16(word);
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word_buffer[i] = add16signed(mult16signed(word, level), word_buffer[i]);
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}
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}
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} else {
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uint16_t *hword_buffer = (uint16_t*)word_buffer;
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uint16_t *hsrc = (uint16_t*)src;
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for (uint32_t i = 0; i<n*2; i++) {
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uint32_t word = unpack8(hsrc[i]);
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if (LIKELY(!self->samples_signed)) {
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word = tosigned16(word);
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}
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word = mult16signed(word, level);
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word = add16signed(word, unpack8(hword_buffer[i]));
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hword_buffer[i] = pack8(word);
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}
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}
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}
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j++;
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length -= n;
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word_buffer += n;
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voice->remaining_buffer += n;
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voice->buffer_length -= n;
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}
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if (length && !voices_active) {
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uint32_t sample_value = self->bits_per_sample == 8
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? 0x80808080 : 0x80008000;
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for (uint32_t i = 0; i<length; i++) {
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word_buffer[i] = sample_value;
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}
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}
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voice->buffer_length -= j;
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voice->remaining_buffer += j;
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}
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audioio_get_buffer_result_t audiomixer_mixer_get_buffer(audiomixer_mixer_obj_t* self,
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@ -403,13 +267,27 @@ audioio_get_buffer_result_t audiomixer_mixer_get_buffer(audiomixer_mixer_obj_t*
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}
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self->use_first_buffer = !self->use_first_buffer;
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bool voices_active = false;
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uint32_t length = self->len / sizeof(uint32_t);
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for (int32_t v = 0; v < self->voice_count; v++) {
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audiomixer_mixervoice_obj_t* voice = MP_OBJ_TO_PTR(self->voice[v]);
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mix_one_voice(self, voice, voices_active, word_buffer, self->len / sizeof(uint32_t));
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mix_one_voice(self, voice, voices_active, word_buffer, length);
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voices_active = true;
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}
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if (!self->samples_signed) {
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if (self->bits_per_sample == 16) {
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for (uint32_t i = 0; i < length; i++) {
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word_buffer[i] = tounsigned16(word_buffer[i]);
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}
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} else {
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for (uint32_t i = 0; i < length; i++) {
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word_buffer[i] = tounsigned8(word_buffer[i]);
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}
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}
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}
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self->read_count += 1;
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} else if (!self->use_first_buffer) {
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*buffer = (uint8_t*) self->first_buffer;
|
||||
|
|
|
|||
|
|
@ -34,7 +34,7 @@
|
|||
|
||||
void common_hal_audiomixer_mixervoice_construct(audiomixer_mixervoice_obj_t *self) {
|
||||
self->sample = NULL;
|
||||
self->level = ((1 << 15) - 1);
|
||||
self->level = 1 << 15;
|
||||
}
|
||||
|
||||
void common_hal_audiomixer_mixervoice_set_parent(audiomixer_mixervoice_obj_t* self, audiomixer_mixer_obj_t *parent) {
|
||||
|
|
@ -42,11 +42,11 @@ void common_hal_audiomixer_mixervoice_set_parent(audiomixer_mixervoice_obj_t* se
|
|||
}
|
||||
|
||||
float common_hal_audiomixer_mixervoice_get_level(audiomixer_mixervoice_obj_t* self) {
|
||||
return ((float) self->level / ((1 << 15) - 1));
|
||||
return ((float) self->level / (1 << 15));
|
||||
}
|
||||
|
||||
void common_hal_audiomixer_mixervoice_set_level(audiomixer_mixervoice_obj_t* self, float level) {
|
||||
self->level = level * ((1 << 15)-1);
|
||||
self->level = level * (1 << 15);
|
||||
}
|
||||
|
||||
void common_hal_audiomixer_mixervoice_play(audiomixer_mixervoice_obj_t* self, mp_obj_t sample, bool loop) {
|
||||
|
|
|
|||
|
|
@ -39,7 +39,7 @@ typedef struct {
|
|||
bool more_data;
|
||||
uint32_t* remaining_buffer;
|
||||
uint32_t buffer_length;
|
||||
int16_t level;
|
||||
uint16_t level;
|
||||
} audiomixer_mixervoice_obj_t;
|
||||
|
||||
|
||||
|
|
|
|||
Loading…
Reference in New Issue