PIC24FJ256GB106XC161.31代码只在选择0到15之间时才工作

使用PIC24FJ256GB106XC161.31注意到下面的代码只在选择0到15之间时才工作，在费力地钻研汇编程序输出之前，我认为下面的快速修改将做出如下选择：UIT88TWDTEMP和DWMMUMASK都是UIT32在调试器中注意到的第二个帖子是，当ByBoice选择＝16；DWTEMP= 0xFFFF 80SO 1 & lt；lt；16＝＝0xFFFF 8000。？？？给出什么



      以下为原文

    using a pic24fj256gb106
xc16 1.31

noticed that the following code appeared to only work when bySelection is between 0 and 15

if(((ptrMenu->dwMenuMask) & (1 << bySelection)) != 0)
      break;


before bothering to dig into the assembler output i figured the following quick modification would do the trick

dwTemp = (1 << bySelection);
if(((ptrMenu->dwMenuMask) & dwTemp) != 0)
       break;


bySelection is uint8_t
dwTemp and dwMenuMask are both uint32_t

From the second posting I noticed in the debugger that when
bySelection = 16;
dwTemp = 0xffff 8000

so 1 << 16 == 0xffff 8000 ???  
what gives



! dwTemp = (1 << bySelection);
0x162B2: MOV.B [W14+16], W0
0x162B4: ZE W0, W0
0x162B6: MOV #0x1, W1
0x162B8: SL W1, W0, W0
0x162BA: ASR W0, #15, W1
0x162BC: MOV W0, [W14+10]
0x162BE: MOV W1, [W14+12]
! if(((ptrMenu->dwMenuMask) & dwTemp) != 0)
0x162C0: MOV [W14+14], W0
0x162C2: MOV [W0+768], W2
0x162C4: MOV [W0+770], W3
0x162C6: MOV [W14+10], W0
0x162C8: MOV [W14+12], W1
0x162CA: MOV W2, W4
0x162CC: MOV W3, W2
0x162CE: MOV W0, W3
0x162D0: MOV W1, W0
0x162D2: AND W4, W3, W4
0x162D4: AND W2, W0, W0
0x162D6: CLR W1
0x162D8: SL W0, #0, W1
0x162DA: MOV #0x0, W0
0x162DC: MOV.D W0, W2
0x162DE: MUL.UU W4, #1, W0
0x162E0: IOR W2, W0, W2
0x162E2: IOR W3, W1, W3
0x162E4: SUB W2, #0x0, [W15]
0x162E6: SUBB W3, #0x0, [W15]
0x162E8: BRA NZ, 0x162F8
! break;