lavr: add x86-optimized functions for mixing 1-to-2 fltp with flt coeffs

libavresample/x86/audio_mix.asm

@@ -150,3 +150,37 @@ cglobal mix_2_to_1_s16p_q8, 3,4,6, src, matrix, len, src1
     sub        lend, mmsize/2
     jg .loop
     REP_RET
+
+;-----------------------------------------------------------------------------
+; void ff_mix_1_to_2_fltp_flt(float **src, float **matrix, int len,
+;                             int out_ch, int in_ch);
+;-----------------------------------------------------------------------------
+
+%macro MIX_1_TO_2_FLTP_FLT 0
+cglobal mix_1_to_2_fltp_flt, 3,5,4, src0, matrix0, len, src1, matrix1
+    mov       src1q, [src0q+gprsize]
+    mov       src0q, [src0q]
+    sub       src1q, src0q
+    mov    matrix1q, [matrix0q+gprsize]
+    mov    matrix0q, [matrix0q]
+    VBROADCASTSS m2, [matrix0q]
+    VBROADCASTSS m3, [matrix1q]
+    ALIGN 16
+.loop:
+    mova         m0, [src0q]
+    mulps        m1, m0, m3
+    mulps        m0, m0, m2
+    mova  [src0q      ], m0
+    mova  [src0q+src1q], m1
+    add       src0q, mmsize
+    sub        lend, mmsize/4
+    jg .loop
+    REP_RET
+%endmacro
+
+INIT_XMM sse
+MIX_1_TO_2_FLTP_FLT
+%if HAVE_AVX
+INIT_YMM avx
+MIX_1_TO_2_FLTP_FLT
+%endif