WinMIps64 instruction set experiment

MIPS

Register type

Arithmetic and addressing instructions

Arithmetic Instructions

! ! ! Arithmetic operation instructions cannot be used for addresses! ! !

Simple addition and subtraction are as follows:


For multiplication and division, there are special registers: Lo and Hi, which correspond to the low and high bits of the 64-bit storage after multiplication and division, respectively.

Load / Store

Only these two instructions can operate on the address.
example:

lw	register_destination, RAM_source ；load a word
lb	register_destination, RAM_source ；load a byte

sw	register_source, RAM_destination
sb	register_source, RAM_destination

load immediate:
li  register_dedstination, 5

Indirect and Based Addressing

load address:

la $t0,val   ;$t0 = address of val ----($t0)=val
lw $t0,4($t1) ; $t0 = address of ($t1+4)

Sample program:

		.data
array1:		.space	12		
#  declare 12 bytes of storage to hold array of 3 integers
#  定义一个 12字节 长度的数组 array1, 容纳 3个整型
		.text
__start:	la	$t0, array1
 #  load base address of array into register $t0
 #  让 $t0 = 数组首地址
		li	$t1, 5		#  $t1 = 5   ("load immediate")
		sw $t1, ($t0)		
#  first array element set to 5; indirect addressing
# 对于 数组第一个元素赋值 array[0] = $1 = 5
		li $t1, 13		#   $t1 = 13
		sw $t1, 4($t0)		#  second array element set to 13# 对于 数组第二个元素赋值 array[1] = $1 = 13 # (该数组中每个元素地址相距长度就是自身数据类型长度，即4字节， 所以对于array+4就是array[1])
		li $t1, -7		#   $t1 = -7
		sw $t1, 8($t0)		#  third array element set to -7
# 同上， array+8 = （address[array[0])+4）+ 4 = address(array[1]) + 4 = address(array[2])
		done

Program structure

The basic template is as follows:

# Comment giving name of program and description of function
# 说明下程序的目的和作用（其实和高级语言都差不多了）
# Template.s
#Bare-bones outline of MIPS assembly language program


           .data       # variable declarations follow this line
　　　　                # 数据变量声明
                       # ...
														
           .text       # instructions follow this line	
		       # 代码段部分															
main:                  # indicates start of code (first instruction to execute)
                       # 主程序
                       # ...
									
# End of program, leave a blank line afterwards to make SPIM happy
# 必须多给你一行，你才欢？

Data declaration

format for declarations
name             storage_type               value(s)
-->example: val .word  3

lables:
.word  
.byte
.space 开辟数组空间
.asciiz 用于字符串

System call

Control Structures

Branch

comparison for conditional branches is built into instruction
		b	target		#  unconditional branch to program label target
		beq	$t0,$t1,target	#  branch to target if  $t0 = $t1
		bne	$t0,$t1,target	#  branch to target if  $t0 != $t1
		slt $t0,$t1,target	#  branch to target if  $t0 < $t1
		还有其它的可以自己翻阅上传的文件。

Jump

j	target	　　　　 
#  unconditional jump to program label target 看到就跳， 不用考虑任何条件
jr	$t3		
#  jump to address contained in $t3 ("jump register") 类似相对寻址，跳到该寄存器给出的地址处

Subroutine Calls

jal sub_label ;跳转到指定位置，且保存之前的pc于$ra寄存器
jr $ra  	;用$ra寄存器恢复之前的pc值

This only applies to one jump. After all, there is only one $ra. If you want to recurse, you still need to use a stack frame.

MIPS instruction set experiment

MinMIPS64 emulator

The big guy about the platform made it very clear: MinMips64 simulator

manual

After writing the code in Notepad, etc., save it as a .s file, use the command line to execute the asm program, and use the code txt as the parameter.

Will prompt no errors and other information, you can run in winmips64.
Open winmips64 and import the txt file:
and the excute->run to program will be executed directly (unless there is a pause such as input).

Then this program has output. If you want to see the output cmd window, you have to select terminal in the windows above, and finally it displays:

IO memory mapping

After DATA is set, the word of CONTROL can be controlled to perform IO operation.

hello world demo

.data
str: .asciiz "Hello World"
CONTROL: .word32 0x10000
DATA: .word32 0x10008

.text
main:
lwu r31,CONTROL(r0) ;$r31 = address of CONTROL register
lwu r30,DATA(r0)        ;$r30 = address of DATA register
daddi r29,r0,4	   ;set control(4):output string
daddi r28,r0,str	   ;get address of str and store in r28
sd r28,(r30)	   ;write address of message to DATA
sd r29,(r31)	   ;output
halt

bubble sort

Code structure

main
	first_show
	sort
	last_show

sort
	loopi
		loopj
	
	looj
		if array[j] > array[j+1] swap
	
	swap
		sd -> array[j]
		sd -> array[j+1]

The complete code will be released later.