Step 7 of Self-writing the CPU (8) -- verify the implementation of the multiplication and accumulation commands

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7.9 Test the effect of the multiplication, accumulation, and subtraction commands

. Org 0x0. set noat. global _ start_start: Ori $1, $ xFFFF sll $1, $ Ori $1, $ xfffb #$1 =-5 is the initial value of Ori $2, $ #$2 = 6 is the register $2 assigned Initial Value mult $1, $2 # Hi = 0 xffffffff # Lo = 0xffffffe2 MADD $1, $2 # Hi = 0 xffffffff # Lo = 0xffffffc4 maddu $1, $2 # Hi = 0x5 # Lo = 0xffffffa6 Msub $1, $2 # Hi = 0x5 # Lo = 0xffffffc4 msubu $1, $2 # Hi = 0 xffffffff # Lo = 0xffffffe2

The program comments show the expected execution results for four consecutive multiply, accumulate, and subtract commands. Modelsim simulation 7-14 is shown. We can see that the multiplication, accumulation, and multiplication, and subtraction commands are correctly implemented. At the same time, we can see that the multiplication, accumulation, and multiplication, and subtraction commands require two clock cycles to be completed.

Code http://download.csdn.net/detail/leishangwen/7858701

Next time, we will introduce the implementation process of Division commands. Please stay tuned!

Step 7 of Self-writing the CPU (8) -- verify the implementation of the multiplication and accumulation commands