ac3enc: NEON optimised float_to_fixed24

Signed-off-by: Mans Rullgard <mans@mansr.com>

libavcodec/arm/ac3dsp_init_arm.c

@@ -27,6 +27,7 @@ void ff_ac3_exponent_min_neon(uint8_t *exp, int num_reuse_blocks, int nb_coefs);
 int ff_ac3_max_msb_abs_int16_neon(const int16_t *src, int len);
 void ff_ac3_lshift_int16_neon(int16_t *src, unsigned len, unsigned shift);
 void ff_ac3_rshift_int32_neon(int32_t *src, unsigned len, unsigned shift);
+void ff_float_to_fixed24_neon(int32_t *dst, const float *src, unsigned int len);
 
 av_cold void ff_ac3dsp_init_arm(AC3DSPContext *c, int bit_exact)
 {
@@ -35,5 +36,6 @@ av_cold void ff_ac3dsp_init_arm(AC3DSPContext *c, int bit_exact)
         c->ac3_max_msb_abs_int16 = ff_ac3_max_msb_abs_int16_neon;
         c->ac3_lshift_int16      = ff_ac3_lshift_int16_neon;
         c->ac3_rshift_int32      = ff_ac3_rshift_int32_neon;
+        c->float_to_fixed24      = ff_float_to_fixed24_neon;
     }
 }

libavcodec/arm/ac3dsp_neon.S

@@ -78,3 +78,17 @@ function ff_ac3_rshift_int32_neon, export=1
         bgt             1b
         bx              lr
 endfunc
+
+function ff_float_to_fixed24_neon, export=1
+1:      vld1.32         {q0-q1},  [r1,:128]!
+        vcvt.s32.f32    q0,  q0,  #24
+        vld1.32         {q2-q3},  [r1,:128]!
+        vcvt.s32.f32    q1,  q1,  #24
+        vcvt.s32.f32    q2,  q2,  #24
+        vst1.32         {q0-q1},  [r0,:128]!
+        vcvt.s32.f32    q3,  q3,  #24
+        vst1.32         {q2-q3},  [r0,:128]!
+        subs            r2,  r2,  #16
+        bgt             1b
+        bx              lr
+endfunc