汇编 MIPS:带伪旋转的十进制到 32 位二进制

Assembly MIPS: decimal to 32-bit binary with pseudo-rotating

我最近发现 MIPS 不旋转位,而只移动它们,所以我一直在挖掘这个洞,为 MIPS 制作一个类似旋转的函数,就我测试它而言它可以工作(函数名为 "shifting" 在下面的代码中)。基本上它存储给定数字的 4 个 MSB,将其转换为 LSB,将数字向左移动 4 位,然后将前 MSB 转换为 LSB 与移位后的数字连接起来。

啊啊啊啊啊啊!数字是"rotated"向左4位。

所以我一直在考虑通过检查每次旋转的最后 4 位来将其用于以完整二进制打印数字。

假设给定的数字如下所示:

aaaa bbbb cccc dddd eeee ffff gggg hhhh iiii

通过向左旋转4位,我们检查aaaa的值:

bbbb cccc dddd eeee ffff gggg hhhh iiii aaaa

并继续旋转,检查并打印bbbb的值:

cccc dddd eeee ffff gggg hhhh iiii aaaa bbbb

直到我们最终得到与开始时相同的数字并检查最后 4 位,iiii:

。 . .

aaaa bbbb cccc dddd eeee ffff gggg hhhh iiii

但是我的代码一直有问题,一直在添加 0,直到编译器崩溃。

.text
main:
li  $v0, 5          #v0 = the given integer
syscall

move $t1, $v0           moving the integer to t1

add $s1, $zero, $zero   #s1 = counter

shifting:
    andi    $t2, $t1, 0xF0000000    #t2 = the 4 MSB's that get pushed to the left
    srl     $t3, $t2, 28        #turning them to LSB's

    sll     $t4, $t1, 4         #shifting the integer

    or      $t5, $t3, $t4       #$t5 = the pseudo-rotated number


loop:
    andi    $t6, $t5, 0xF       #isolating the 4 new LSB's
    beq $t6, 0xF, one           #print 1's where is necessary 

    li  $v0, 1         #else print 0's
    la  $a0, 0
    syscall
j shifting  

next:
    addi    $s1, $s1, 1
    beq     $s1, 32, exit    #stop printing at 32 numbers

one:                #printing the aces
    li  $v0, 1
    la  $a0, 1
    syscall
j shifting  

exit:
li  $v0, 10
syscall

看来我对这件事想得太多了,我真的跟不上循环了。

我的代码有什么问题?

所以我暂时失去了一点注意力,但我开始工作了:

.text
main:
li  $v0, 5          #v0 = the given integer
syscall

move    $t1, $v0        #moving integer to t1

add $s2, $zero, $zero   #counter for all the 4bits

shifting:

    andi    $t2, $t1, 0xF0000000    #t2 = the 4 MSB's that get pushed to the left
    srl $t3, $t2, 28         #turning them to LSB's

    sll     $t4, $t1, 4          #shifting the integer

    or  $t5, $t3, $t4       #$t5 = the pseudo-rotated number  

    andi    $t6, $t5, 0xF       #isolating the 4 LSB's

check:  

    beq     $s2, 8, exit        #32 bits = 8x 4bits
    addi    $s2, $s2, 1     #adding the counter for the 4bits

    li  $v0, 11         #spaces between 4bits
    li  $a0, ' '
    syscall

    add $s1, $zero, $zero   #counter for each bit in a 4bit

bts:
    andi    $a0, $t6, 8         #4bit AND 8
    beq     $a0, 8, one     #if a0 = 8 print 1

    li  $v0, 1          #else print 0
    li  $a0, 0
    syscall

next:
    sll     $t6, $t6, 1     #shift the bit to the left

    addi    $s1, $s1, 1     #adding the counter for one 4bit

    move    $t1, $t5        #shift the pseudo-rotated number next time

    beq $s1, 4, shifting    #make sure the 4bit will have 4 bits

one:            #function that prints 1's
    li  $v0, 1
    li  $a0, 1
    syscall
j next  

exit:
li  $v0, 10
syscall

有空的时候,我会尝试让它适用于浮点数。