Legup Wiki

Timing analysis of ADPCM

FMax : 68.58 MHz

Start signal: LEGUP_function_call_88

End signal: upzero_preheader_55_reg

if ( (cur_state == LEGUP_function_call_88) ) begin upzero_memory_controller_out_b = memory_controller_out_b; end

upzero upzero_inst ( . . . .memory_controller_out_b (upzero_memory_controller_out_b), );

/* %55 = add nsw i32 %51, %54*/

upzero_preheader_55 = (upzero_preheader_51 + upzero_preheader_54);

/* %54 = ashr i32 %53, 8*/

upzero_preheader_54 = ($signed(upzero_preheader_53) »> 32'd8);

/* %53 = mul nsw i32 %52, 255*/

upzero_preheader_53 = (upzero_preheader_52 * 32'd255);

/* %52 = load i32* %scevgep5.3, align 4, !tbaa !0*/

upzero_preheader_52 = memory_controller_out_b[31:0];

/* %51 = or i32 %50, 128*/

upzero_preheader_51 = (upzero_preheader_50 | 32'd128);

/* %50 = and i32 %49, -256*/

upzero_preheader_50 = (upzero_preheader_49 & -32'd256);

/* %49 = ashr i32 %48, 31*/

upzero_preheader_49 = ($signed(upzero_preheader_48) »> 32'd31);

/* %48 = mul nsw i32 %47, %dlt*/

upzero_preheader_48 = (upzero_preheader_47 * arg_dlt);

/* %47 = load i32* %scevgep.3, align 4, !tbaa !0*/

upzero_preheader_47 = memory_controller_out_a[31:0];

Corresponding C code:

in fuction upzero:

  **if ((long) dlt * dlti[i] >= 0)
    wd2 = 128;
  else
    wd2 = -128;
  wd3 = (int) ((255L * bli[i]) >> 8L);	/* leak factor of 255/256 */
  bli[i] = wd2 + wd3;**