static int _do_rematrixing(AC3DecodeContext *ctx, int start, int end) { float tmp0, tmp1; while (start < end) { tmp0 = ctx->samples[start]; tmp1 = (ctx->samples + 256)[start]; ctx->samples[start] = tmp0 + tmp1; (ctx->samples + 256)[start] = tmp0 - tmp1; start++; } return 0; }