cor.asm

文件为美军4800bps语音压缩编码标准在TI的DSP芯片TMS320C5X上的实时实现源代码。

	.version        50
	.mmregs
	.bss T1,1
	.bss T2,1
	.BSS COR,11*2		;COR[11] long type
	.bss SIGNAL,240
FLEN	.SET 240
HFLEN   .SET 120	;FLEN/2
HFLEN_1 .SET 120-1

	.data

S0	.copy "s_10.dat"		;240 signal values
TCOR	.COPY "C_10.DAT"

	.text

	CALL C50_INIT
	call GETCOR
here:	NOP
	B here
	.include "c50_init.asm"
GETCOR
	LDP #0
	SPLK #S0,BMAR
	MAR *,AR0
	lar ar0,#SIGNAL		;AR0->SIGNAL
	RPT #239
	  BLPD BMAR,*+		;S0[]->SIGNAL[240]
	;-------------------
	LAR AR0,#SIGNAL
	LAR AR1,#COR		;AR1->COR,AR0->SIGNAL
	LAR AR2,AR0
	LAR AR6,#HFLEN_1	;120-i,AR6--
	LAR AR7,#10		;REPEAT COUNT
	SPM 3
	;------------ARP=0
	;-------Begin calculating c0
	ZAP
	RPT #HFLEN_1
	  MAC #SIGNAL,*+
	APAC			;120 values sum ACC+=PREG*(2**shift)
	SFR			;ACC>>=1
	SACB			;ACC->ACCB
	;-----------
	ZAP
	RPT AR6			;AR6->RPTC
	  MAC #SIGNAL+120,*+
	APAC			;(AR6) values sum ACC+=PREG*(2**shift)
	SFR			;ACC>>=1
	ADDB			;ACC+=ACCB
	;----------------
	SUB #256
	BCND GLT256,LEQ		;JUMP IF C0<256
	;-----IF C0>=256-----------
	;----GET C----------
	ADD #256
	MAR *,AR1
	SACL *+   		;ARP=1
	SACH *+,0,AR6		;ARP=6
	;-----------------
	MAR *-,AR2		;AR6--,120-i
	MAR *+,AR7		;AR2++,*signal++
	MAR *-,AR0
	LAR AR0,AR2		;AR2->AR0 ,ARP=0
	B COR_256
	;----IF C0<256-----------
GLT256
	SPM 0
	LAR AR0,#SIGNAL
	;--------------------ARP=0
COR_256
	ZAP
	RPT #HFLEN_1
	  MAC #SIGNAL,*+
	APAC			;120 values sum ACC+=PREG*(2**shift)
	SFR			;ACC>>=1
	SACB			;ACC->ACCB
	;-----------
	ZAP
	RPT AR6			;AR6->RPTC
	  MAC #SIGNAL+120,*+
	APAC			;120 values sum ACC+=PREG*(2**shift)
	SFR			;ACC>>=1
	ADDB			;ACC+=ACCB
	;----GET C----------
	MAR *,AR1
	SACL *+   		;ARP=1
	SACH *+,0,AR6		;ARP=6
	;-----------------
	MAR *-,AR2		;AR6--,120-i
	MAR *+,AR7		;AR2++,*signal++
	LAR AR0,AR2		;AR2->AR0 ,ARP=7
	BANZ COR_256,*-,AR0

	RET
	.end