1#define TBRL 268 2#define TBRU 269 /* Time base Upper/Lower (Reading) */ 3 4/* 5 * time stamp counter; _cycles since power up 6 * Runs at fasthz/4 cycles per second (m->clkin>>3) 7 */ 8TEXT cycles(SB),1,$0 9loop: 10 MOVW SPR(TBRU),R7 11 MOVW SPR(TBRL),R8 12 MOVW SPR(TBRU),R5 13 CMP R5,R7 14 BNE loop 15 MOVW R7,0(R3) 16 MOVW R8,4(R3) 17 RETURN 18