Question

我正在尝试将源代码映射到目标代码。我正在创建新的结构，在Code Composer中针对不同的代码优化级别构建这些结构，并将它们与源代码进行比较。

我面临的问题是，当DSP生成汇编代码时，它为优化级别2插入了几条OR语句，鉴于构造中没有OR语句，这很难理解。感谢对此的任何帮助。我在下面添加了Construct和2个dissasembly文件。谢谢。

这是我的构造的样子

void Construct157_While_If(Int32 param157_input1, Int32 param157_input2)
{
     Int32 var157_local1 = NUM_ZERO ;
     Int32 var157_local2 = NUM_ZERO ;

     var157_local1 = param157_input1 ;
     var157_local2 = param157_input2 ;

while( (!var157_local1) && (var157_local2 == NUM_ZERO ))
    {
        if(var157_local2 == NUM_ONE)
        {
            var157_local2++;
            var157_local1++;
        }
    }
}

这是优化关闭的样子

TEXT Section .text (Little Endian), 0x60 bytes at 0x0 
00000000             _Construct157_While_If__FiT1:
00000000             .text:
00000000       8cf7           SUBAW.D2      B15,0x4,B15
00000002       7246           MV.L1X        B4,A3
00000004       ac45 ||        STW.D2T1      A4,*B15[1]
00000006       cc35           STW.D2T1      A3,*B15[2]
00000008       0627           MVK.L2        0,B4
0000000a       fc45           STW.D2T2      B4,*B15[3]
0000000c       9cc5           STW.D2T2      B4,*B15[4]
0000000e       9247           MV.L2X        A4,B4
00000010       fc45           STW.D2T2      B4,*B15[3]
00000012       91c7           MV.L2X        A3,B4
00000014       9cc5           STW.D2T2      B4,*B15[4]
00000016       3247           MV.L2X        A4,B1
00000018   40288120    [ B1]  BNOP.S1       $C$L3 (PC+80 = 0x00000050),4
0000001c   e7e00002           .fphead       n, l, W, BU, nobr, nosat, 0111111b
00000020   00100fda           MV.L2         B4,B0
00000024   2018a120    [ B0]  BNOP.S1       $C$L3 (PC+48 = 0x00000050),5
00000028             $C$L1:
00000028             $C$DW$L$_Construct157_While_If__FiT1$3$B:
00000028       804f           MV.S2         B0,B4
0000002a       2027 ||        CMPEQ.L2      1,B0,B0
0000002c   300da120    [!B0]  BNOP.S1       $C$DW$L$_Construct157_While_If__FiT1$4$E (PC+26 = 0x0000003a),5
00000030             $C$DW$L$_Construct157_While_If__FiT1$3$E:
00000030             $C$DW$L$_Construct157_While_If__FiT1$4$B:
00000030       2641           ADD.L2        B4,1,B4
00000032       9cc5           STW.D2T2      B4,*B15[4]
00000034       fc4d           LDW.D2T2      *B15[3],B4
00000036       2641           ADD.L2        B4,1,B4
00000038       fc45           STW.D2T2      B4,*B15[3]
0000003a             $C$DW$L$_Construct157_While_If__FiT1$4$E:
0000003a             $C$L2:
0000003a             $C$DW$L$_Construct157_While_If__FiT1$5$B:
0000003a       fc0d           LDW.D2T2      *B15[3],B0
0000003c   ee900010           .fphead       p, l, W, BU, nobr, nosat, 1110100b
00000040   2004a120    [ B0]  BNOP.S1       $C$L3 (PC+16 = 0x00000050),5
00000044             $C$DW$L$_Construct157_While_If__FiT1$5$E:
00000044             $C$DW$L$_Construct157_While_If__FiT1$6$B:
00000044   003c82e6           LDW.D2T2      *+B15[4],B0
00000048   00006000           NOP           4
0000004c   3ffaa120    [!B0]  BNOP.S1       $C$L1 (PC-24 = 0x00000028),5
00000050             $C$L3:
00000050             $C$DW$L$_Construct157_While_If__FiT1$6$E:
00000050   07800852           ADDK.S2       16,B15
00000054   008ca362           BNOP.S2       B3,5
00000058   00000000           NOP           
0000005c   00000000           NOP

这是优化级别2的混乱外观

TEXT Section .text (Little Endian), 0x40 bytes at 0x0 
00000000             _Construct157_While_If__FiT1:
00000000             .text:
00000000       9628           OR.L1X        A4,B4,A0
00000002       6866    [!A0]  MVK.L1        1,A0
00000004   c01aa120 || [ A0]  BNOP.S1       $C$DW$L$_Construct157_While_If__FiT1$3$E (PC+52 = 0x00000034),5
00000008             $C$L1:
00000008   c083e001    [ A0]  SPLOOPW       2
0000000c       a247 ||        MV.L2         B4,B5
0000000e             $C$L2:
0000000e             $C$DW$L$_Construct157_While_If__FiT1$3$B:
0000000e       2e66           SPMASK        S2
00000010       924f ||^       MV.S2X        A4,B4
00000012       2aa7 ||        CMPEQ.L2      1,B5,B1
00000014   4210205b    [ B1]  ADD.L2        1,B4,B4
00000018   4280012a || [ B1]  MVK.S2        0x0002,B5
0000001c   e3200182           .fphead       n, l, W, BU, nobr, nosat, 0011001b
00000020   0010a6e2           OR.S2         B5,B4,B0
00000024   2000a358    [ B0]  MVK.L1        0,A0
00000028   00002000           NOP           2
0000002c   00000000           NOP           
00000030   00034000           SPKERNEL      0,0
00000034             $C$DW$L$_Construct157_While_If__FiT1$3$E:

汇编代码与源代码的映射

0 个答案: