div.s43

来自「msp430-book」· S43 代码 · 共 47 行

;******************************************************************************
;   MSP430FG439 Integer-Integer division using Algorithm described in Hamacher
;
;   Description: This code performs a 16-bit integer-integer division 
;                of numbers to return an 16-bit integer
;                 
;
;   Note:        This code assumes 32.768kHz XTAL on LFXT1 on the MSP430FG439 
;
;                  MSP430FG439
;               -----------------
;              |              XIN|-  
;              |                 | 32.768kHz
;              |             XOUT|-
;              |                 |
;
;
;
;   K. Venkat
;   Texas Instruments Inc.
;   July 2006
;   Built with IAR Embedded Workbench Version: 3.41A
;*******************************************************************************/
	    public div_hamacher

	    RSEG CODE
div_hamacher:

            ;   R12 has dividend  
            ;   R14 has divisor
        
            mov.w     #16,R11
            clr.w     R13
start:      rla.w     R12
            rlc.w     R13
            bis.w     #1, R12
            sub.w     R14,R13
            jge       loc1
            add.w     R14,R13
            bic.w     #1, R12
loc1:       dec.w     R11
            cmp.w     #0,R11
            jnz       start
            ret
            END