XC16的神秘汇编符号问题

我使用的是一个方便的交换机CASE汇编宏，它是通过将当前的测试值与当前实例的XOR一起进行测试，并且测试为零：“Switter”宏只是将汇编器变量“PREVTEST”初始化为零，并将CASE宏更新PREVTEST调用到经过的论证中。T的值，为下一个case语句设置。到目前为止，它一直在为我工作，这里的组装正确：四个文字参数的值是0x74、0x72、0x72和0x66。您可以看到，每个XOR的文字是XORY语句与当前语句的文字的结果。现在，我在同一个程序中的其他地方调用相同的宏，并且由于某些原因，汇编变量VestToT似乎没有得到更新：这里是文字参数。值是0x71,0xe1和0xe2，您可以看到这些值出现在XOR指令中，而没有与前一个调用的值进行XOR。宏中的汇编器“^”（XOR）运算符没有执行，或者PREPTEST的值为0。但它是相同的宏定义，在程序的其他地方工作！唯一的区别是工作和非工作调用在不同的部分，但这两个部分都具有相同的属性。我尝试使用.SET和=汇编操作符，并且我尝试了替代和AG＆AMP格式作为参数引用，没有用。是的，我知道有很多。我可以用其他方法来实现这个代码，但是我想知道这里发生了什么，如果有人有任何想法的话。谢谢）



      以下为原文

    I'm using a handy switch-case assembler macro that works by XOR'ing the previous case's test value with the current instance's, and testing for zero:

.macro switch
.equ prevtest,0
.endm

.macro caseb value,dest
xor.b value^prevtest,w0
bra z,dest
.equ prevtest,value
.endm

The "switch" macro just initializes the assembler variable "prevtest" to zero, and invocations of the case macro update prevtest to the passed argument's value, setting it up for the next case statement. It's been working a treat for me until now, and here it's assembled correctly:

                                                 3367: GOTCOMMAND:
012DC0 BFCAE3 MOV.B 0xAE3, WREG 3368: mov.b RXTYPE,wreg
                                                  3369: switch
012DC2 B2C740 XOR.B #0x74, W0 3370: caseb #cmd_SPIN,DOSPIN
012DC6 B2C060 XOR.B #0x6, W0 3371: caseb #cmd_NEWSCHED,ERASESCHED
012DCA B2C010 XOR.B #0x1, W0 3372: caseb #cmd_SCHEDDATA,DOSCHEDDATA
012DCE B2C150 XOR.B #0x15, W0 3373: caseb #cmd_FINISHSCHED,DOFINISHSCHED

The values of the four literal arguments are 0x74, 0x72, 0x73, and 0x66. You can see that the literal of each XOR is the result of XOR'ing the previous statement's literal with the current one's.

Now I'm invoking the same macro elsewhere in the same program, and for some reason the assembler variable prevtest doesn't appear to be getting updated:

                                                 884: BL_GOTCOMMAND:
000260 BFCAE3 MOV.B 0xAE3, WREG 885: mov.b RXTYPE,wreg
                                                  886: switch
000262 B2C710 XOR.B #0x71, W0 887: caseb #cmd_GET,BL_DOGET
000266 B2CE10 XOR.B #0xE1, W0 888: caseb #cmd_ERASEFW,BL_ERASEFW
00026A B2CE20 XOR.B #0xE2, W0 889: caseb #cmd_WRITEFW,BL_WRITEFW

Here the literal argument values are 0x71, 0xE1, and 0xE2 and you can see those values appear in the XOR instructions without having been XOR'd with the previous invocation's value. Either the assembler "^" (xor) operator in the macro is not being executed, or the value of prevtest is 0. But it's the same macro definition that works elsewhere in the program! The only difference is that the working and non-working invocations are in different sections, but both sections have the same attributes.

I tried using .set and = assembler operators, and I tried the alternative &arg& format for the argument reference, to no avail.

Yes, I know there are lots of other ways I can implement this code, but I'd like to know what's going on here, if anyone has any ideas. Thanks :)