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我必须为以下内容编写一个微处理器 8085 汇编语言代码：-

从 2400H/0C20H 开始，6 个国家的人口普查存储在 18 个位置。第一个字节是代码编号（可以从 00H 到 05H），接下来的 2 个字节是二进制的国家人口（每个国家占 3 个位置）。我必须找到人口最多的国家，并将其国家代码存储在位置 2500H/0C90H。

我在整个互联网上进行了搜索，但找不到我们如何比较 8085 中的两个 2 字节二进制数？如果您能提供帮助将不胜感激。

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3 回答 3

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Solved Finally with the help of a friend. Here it is :-

KickOff 2050H                  ;where to start the program
Org 2050H                      ;where to start the code

lxi sp,23ffH                   ;initializing stack pointer to 23ffH
lxi hl,0000H                   ;resulting population to 00 initially for comparison
shld 2501H                     ;store this poulation (00) to 2501h
lxi hl,2400h                   ;now load the address of start loc of data

mvi c,06h                      ;counter for 6 countries

loop:
     mov d,m                   ;store the index of current country in d register
     inx hl                    ;increase hl pair
     mov b,m                   ;store the first byte of current population in b
     inx hl   
     mov e,m                   ;store the second byte of current population in e
     push hl                   ;push hl pair onto stack for later use
     lxi hl,2501h               
     mov a,b

     cmp m                     ;compare first byte (a-m) will set c=1 if m>a
     jc next                   ;if carry do nothing
     jz next1                  ;if z=1, they are equal so we compare next two bytes
     mov m,a                   ;if current greater than previous value then change values of 2501 and 2502 and also index
     inx hl                     
     mov m,e
     mov a,d
     sta 2500h                 ;ab kitna samjaye, kr lo khud se
     jmp next

next1:
     inx hl
     mov a,e
     cmp m
     jc next
     mov m,e
     dcx hl
     mov m,b
     mov a,d
     sta 2500h

next:
     pop hl
     inx hl
     dcr c
     jnz loop
     hlt

thank you all for your answers !! :)

于 2013-09-30T19:26:31.213 回答
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mvi a, 1st no.  
mvi b, 2nd no.  
cmp b  
jc go   
mov a,b  
go: sta 0020h  
hlt
于 2014-01-17T12:55:59.933 回答
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在 8 位 CPU 上，您比较第一个（= 最高）字节。如果相等，则比较第二个（= 较低）字节。比较 32 位或 64 位数字时，您继续使用第三个字节，依此类推。当字节不相等时停止比较。

在 Z80 上，您还可以使用指令“SBC HL,DE”进行 16 位比较。但是，此指令在 8085 上不存在。

8 位处理器的示例：

 LOAD register1, [high byte of A]
 LOAD register2, [high byte of B]
 COMPARE register1, register2
 JUMP_IF_EQUAL was_equal
   // -- This is used for 32- and 64-bit numbers only --
 LOAD register1, [second byte of A]
 LOAD register2, [second byte of B]
 COMPARE register1, register2
 JUMP_IF_EQUAL was_equal
   ...
   // -- --
 LOAD register1, [low byte of A]
 LOAD register2, [low byte of B]
 COMPARE register1, register2
was_equal:
  // Here the status flags are set as if a 16-bit UNSIGNED
  // COMPARE had been done.

用处理器的正确指令替换指令“加载”等！

有符号数比较更难！

于 2013-09-30T07:40:44.440 回答