Rev 1595 | Blame | Compare with Previous | Last modification | View Log | RSS feed
;-----------------------------------------------------------------------------;; Fast integer squareroot routines for avr-gcc project (C)ChaN, 2008; http://elm-chan.org/docs/avrlib/sqrt32.S;-----------------------------------------------------------------------------;; uint16_t isqrt32 (uint32_t n);; uint8_t isqrt16 (uint16_t n);; uint16_t ihypot (int16_t x, int16_t y);;-----------------------------------------------------------------------------:; 32bit integer squareroot;-----------------------------------------------------------------------------;; uint16_t isqrt32 (; uint32_t n; );;; Return Value:; Squareroot of n.;; Size = 53 words; Clock = 532..548 cycles; Stack = 0 byte.global isqrt32.func isqrt32isqrt32:clr r0clr r18clr r19clr r20ldi r21, 1clr r27clr r30clr r31ldi r26, 161: lsl r22rol r23rol r24rol r25rol r0rol r18rol r19rol r20lsl r22rol r23rol r24rol r25rol r0rol r18rol r19rol r20brpl 2fadd r0, r21adc r18, r27adc r19, r30adc r20, r31rjmp 3f2: sub r0, r21sbc r18, r27sbc r19, r30sbc r20, r313: lsl r21rol r27rol r30andi r21, 0b11111000ori r21, 0b00000101sbrc r20, 7subi r21, 2dec r26brne 1blsr r30ror r27ror r21lsr r30ror r27ror r21mov r24, r21mov r25, r27ret.endfunc;-----------------------------------------------------------------------------:; 16bit integer squareroot;-----------------------------------------------------------------------------;; uint8_t isqrt16 (; uint16_t n; );;; Return Value:; Squareroot of n.;; Size = 33 words; Clock = 181..189 cycles; Stack = 0 byte.global isqrt16.func isqrt16isqrt16:clr r18clr r19ldi r20, 1clr r21ldi r22, 81: lsl r24rol r25rol r18rol r19lsl r24rol r25rol r18rol r19brpl 2fadd r18, r20adc r19, r21rjmp 3f2: sub r18, r20sbc r19, r213: lsl r20rol r21andi r20, 0b11111000ori r20, 0b00000101sbrc r19, 7subi r20, 2dec r22brne 1blsr r21ror r20lsr r21ror r20mov r24, r20ret.endfunc;-----------------------------------------------------------------------------:; 16bit integer hypot (megaAVR is required);-----------------------------------------------------------------------------;; uint16_t ihypot (; int16_t x,; int16_t y; );;; Return Value:; Squareroot of (x*x + y*y);; Size = 42 words; Clock = 581..597 cycles; Stack = 0 byte.global ihypot.func ihypotihypot:clr r26sbrs r25, 7rjmp 1fcom r24com r25adc r24, r26adc r25, r261: sbrs r23, 7rjmp 2fcom r22com r23adc r22, r26adc r23, r262: mul r22, r22movw r18, r0mul r23, r23movw r20, r0mul r22, r23add r19, r0adc r20, r1adc r21, r26add r19, r0adc r20, r1adc r21, r26mul r24, r24movw r30, r0mul r25, r25add r18, r30adc r19, r31adc r20, r0adc r21, r1mul r24, r25add r19, r0adc r20, r1adc r21, r26add r19, r0adc r20, r1adc r21, r26movw r24, r20movw r22, r18clr r1rjmp isqrt32.endfunc