AVR乘除法子程序Word文件下载.docx

AVR乘除法子程序Word文件下载.docx

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rjmpRESET;

resethandle

*"

mpy8u"

-8x8BitUnsignedMultiplication

*Numberofcycles:

65

*Lowregistersused:

None

*Highregistersused:

3（mc8u,mp8u/m8uL,m8uH）

*Note:

ResultLowbyteandthemultipliersharethesameregister.

*Thiscausesthemultipliertobeoverwrittenbytheresult.

*****SubroutineRegisterVariables

.defmc8u=r16;

multiplicand

.defmp8u=r17;

multiplier

.defm8uL=r17;

resultLowbyte

.defm8uH=r18;

resultHighbyte

.defcycle=r31

*****Code

mpy8u:

ldicycle,8

clrm8uH;

clearresultHighbyte

lsrmp8u;

shiftmultiplier

m8u:

brccnoad80;

ifcarryset

addm8uH,mc8u;

addmultiplicandtoresultHighbyte

noad80:

rorm8uH;

shiftrightresultHighbyte

rorm8uL;

rotaterightresultLbyteandmultiplier

deccycle

brnem8u

ret

*****2字节乘法子程序

--------16bit*16bit----aH.aL*bH.bL=result3.2.1.0------------

---或---16bit*8bit-----aH.aL*bL=Result3.2.1-----------------

******************************************************************

.defaL=r16;

multiplicandlowbyte//被乘数

.defaH=r17;

multiplicandhighbyte

.defbL=r18;

multiplierlowbyte//乘数

.defbH=r19;

multiplierhighbyte

.defresult0=r18;

resultbyte0（LSB）

.defresult1=r19;

resultbyte1

.defresult2=r20;

resultbyte2

.defresult3=r21;

resultbyte3（MSB）

m16_8u:

ldiR19,0

rjmpmBegin

m16_16u:

ldicycle,16

mBegin:

clrresult3;

clear2highestbytesofresult

clrresult2

lsrbH;

乘数/2

rorbL;

C<

-Rd.0Rd.0<

-Rd.1Rd.15<

-0

m16_16u1:

brccnoadd;

若Rd.0=1//（ifcarryset）

addresult2,aL;

被乘数低字节加到结果的2字节

adcresult3,aH;

被乘数高字节加到结果的3字节

noadd:

rorresult3;

shiftrightresultbyte3

rorresult2;

rotaterightresultbyte2

rorresult1;

rotateresultbyte1andmultiplierHigh

rorresult0;

rotateresultbyte0andmultiplierLow

deccycle

brnem16_16u1

div8u"

-8/8BitUnsignedDivision

*Thissubroutinedividesthetworegistervariables"

dd8u"

（dividend）and

dv8u"

（divisor）.Theresultisplacedin"

dres8u"

andtheremainderin

drem8u"

.

*Numberofwords:

94+return

1（drem8u）

2（dres8u/dd8u,dv8u,cycle）

.defdrem8u=r15;

remainder

.defdres8u=r16;

result

.defdd8u=r16;

dividend

.defdv8u=r17;

divisor

.defcycle=r18

*****Code**********R16/R17=R16+R15*********************

div8u:

clrdrem8u;

clearremainderandcarry

ldicycle,9;

8+1

d8u_0:

roldd8u;

shiftleftdividend

breqd8u_2

roldrem8u;

shiftdividendintoremainder

subdrem8u,dv8u;

remainder=remainder-divisor

brccd8u_1;

ifresultnegative

adddrem8u,dv8u;

restoreremainder

clc;

clearcarrytobeshiftedintoresult

rjmpd8u_0;

else

d8u_1:

sec;

setcarrytobeshiftedintoresult

rjmpd8u_0

d8u_2:

66+return

50/58/66（Min/Avg/Max）+return

2（dres8u/dd8u,dv8u）

subdrem8u,drem8u;

shiftleftdividend

rjmpd8u_2;

setcarrytobeshiftedintoresult

brccd8u_3;

rjmpd8u_4;

d8u_3:

d8u_4:

brccd8u_5;

rjmpd8u_6;

d8u_5:

d8u_6:

brccd8u_7;

rjmpd8u_8;

d8u_7:

d8u_8:

brccd8u_9;

rjmpd8u_10;

d8u_9:

d8u_10:

brccd8u_11;

rjmpd8u_12;

d8u_11:

d8u_12:

brccd8u_13;

rjmpd8u_14;

d8u_13:

d8u_14:

brccd8u_15;

rjmpd8u_16;

d8u_15:

d8u_16:

------------------div16_8u----16/8bit----R20R19/R18=R20R19+R17R16-------------------

.defdres16uL=r19

.defdres16uH=r20

.defdd16uL=r19

.defdd16uH=r20

.defdv8u=r18

.defdcnt16u=r22

.defdrem16uL=r16

.defdrem16uH=r17

div16_8u:

clrdrem16uL;

clearremainderLowbyte

subdrem16uH,drem16uH;

clearremainderHighbyteandcarry

ldidcnt16u,17

d16u_1:

roldd16uL;

roldd16uH

decdcnt16u

breqd16u_3;

完成?

跳出

roldrem16uL;

roldrem16uH

subdrem16uL,dv8u;

brccd16u_2;

adddrem16uL,dv8u;

rjmpd16u_1;

d16u_2:

sec

rjmpd16u_1

d16u_3:

ret

--------------------------------16bit/16bit-----------------------------------------

.defdrem16uL=r14

.defdrem16uH=r15

.defdres16uL=r16

.defdres16uH=r17

.defdd16uL=r16

.defdd16uH=r17

.defdv16uL=r18

.defdv16uH=r19

.defdcnt16u=r20

div16u:

subdrem16uL,dv16uL;

sbcdrem16uH,dv16uH;

adddrem16uL,dv16uL;

adcdrem16uH,dv16uH

div16u"

-16/16BitUnsignedDivision

*Thissubroutinedividesthetwo16-bitnumbers

dd8uH:

dd8uL"

（dividend）and"

dv16uH:

dv16uL"

（divisor）.

*Theresultisplacedin"

dres16uH:

dres16uL"

drem16uH:

drem16uL"

196+return

148/173/196（Min/Avg/Max）

2（drem16uL,drem16uH）

4（dres16uL/dd16uL,dres16uH/dd16uH,dv16uL,dv16uH）

.defdrem1