发个48时钟的2字节乘以两字节的51汇编。

1万 · 2009-5-20 09:01

知道老hot和邓mm 高人经常来这里。
今天看资料，有点疑问发一下。

8-bit (8051)
MOV A, XL ; 2 bytes
MOV B, YL ; 3 bytes
MUL AB; 1 byte
MOV R0, A; 1 byte
MOV R1, B; 3 bytes
MOV A, XL ; 2 bytes
MOV B, YH ; 3 bytes
MUL AB; 1 byte
ADD A, R1; 1 byte
MOV R1, A; 1 byte
MOV A, B ; 2 bytes
ADDC A, #0 ; 2 bytes
MOV R2, A; 1 byte
MOV A, XH ; 2 bytes
MOV B, YL ; 3 bytes
MUL AB; 1 byte
ADD A, R1; 1 byte
MOV R1, A; 1 byte
MOV A, B ; 2 bytes
ADDC A, R2 ; 1 bytes
MOV R2, A; 1 byte
MOV A, XH ; 2 bytes
MOV B, YH ; 3 bytes
MUL AB; 1 byte
ADD A, R2; 1 byte
MOV R2, A; 1 byte
MOV A, B ; 2 bytes
ADDC A, #0 ; 2 bytes
MOV R3, A; 1 byte
Time: 48 clock cycles
Code size: 48 bytes

16-bit
MOV R4,&0130h
MOV R5,&0138h
MOV SumLo,R6
MOV SumHi,R7
(Operands are moved
to and from a memory
mapped hardware
multiply unit)
Time: 8 clock cycles
Code size: 8 bytes

ARM Cortex-M0
MULS r0,r1,r0
Time: 1 clock cycle
Code size: 2 bytes