mat_vecn.asm

DSP程序TI常用例程MatRix,可以参考使用

;
;   calculates c = a x b
;   where:  a is m x n
;	    b is n x 1
;
;   calling from c:
;
;   float   a[m][n];
;   float   b[n];
;   float   c[n];
;
;   int     m;
;   int     n;
;
;   void    mat_vecn( m, n, c, a, b )
;
;      James M. Patterson
;      Texas Instruments
;      370 South North Lake Boulevard
;      Altamonte Springs, Florida 32701
;
;
	    .text

	    .global _mat_vecn
FP	    .set    AR3 	;use AR3 as a frame pointer


_mat_vecn:
	    push    FP		    ;save caller's FP
	    ldi     SP, FP	    ;set FP to TOS

	    push    AR4 	    ;save AR4

	    ldi     *-FP(2), AR4    ;get m ( rows in a )
	    ldi     *-FP(3), IR0    ;get n ( length of b )
	    ldi     *-FP(4), AR2    ;get address of c vector
	    ldi     *-FP(5), AR0    ;get address of a matrix
	    ldi     *-FP(6), AR1    ;get address of b vector

	    ldi     IR0, R1
	    subi    1, R1	    ;n - 1 to R1
	    nop     *AR4--	    ;decrement row counter

next:	    ldf 0.0, R0
	    ldf R0, R3		;clear R0, R3

	    rpts    R1		;IR1 has number of a columns

	    mpyf3   *AR0++, *AR1++, R0
	||  addf3   R0, R3, R3		;calculate a c term

	    dbud    AR4, next	;done with all a rows?

	    addf    R0, R3		;complete calculation of c term
	    stf     R3, *AR2++		;and store  it

	    nop     *AR1--(IR0) ;point AR1 back to start of B

	    ;	branch occurs here if taken

	    pop     AR4
	    pop     FP		;restore caller's FP

	    rets		;return

	    .end