qpsk.asm

QPSP

********************************************************
* QPSK解制程序----采用相位选择法 		       *
* fc=1800Hz,RB=2400B		 		       *
********************************************************
	.title	"QPSK.asm"
	.mmregs
	.copy 	"wave.inc"
	.def 	start
inadata	.usect	"buffer",1
inbdata	.usect	"buffer",1
outdata	.usect	"buffer",32
STACK	.usect	"STACK",10
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	.text
start:	LD	#inadata,DP
	STM	#inadata,AR1
	STM	#inbdata,AR2
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input:	nop			;读入两bit的数据
	nop
	LD	*AR1,A
	LD	*AR2,B
	STM	#outdata,AR4
	BC	A1,AGT		;if A>0,then goto A1
	BC	B1,BGT		;if B>0,then goto B1
	STM	#cos225,AR3	;A=0,B=0
	B	OUT
B1:	STM	#cos135,AR3	;A=0,B=1
	B	OUT
A1:	BC	A1B1,BGT
	STM	#cos315,AR3	;A=1,B=0
	B	OUT		
A1B1:	STM	#cos45,AR3	;A=1,B=1
	B	OUT
********************************************************
OUT:	RPT	#31
	MVDD	*AR3+,*AR4+
	nop
	B	input
	.end
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