| //===------------ udivmodqi4.S - uint8 div & mod --------------------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // As described at |
| // https://gcc.gnu.org/wiki/avr-gcc#Exceptions_to_the_Calling_Convention, the |
| // prototype is `struct {uint8, uint8} __udivmodqi4(uint8, uint8)`. |
| // The uint8 quotient is returned via R24, and the uint8 remainder is returned |
| // via R25, while R23 is clobbered. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| .text |
| .align 2 |
| |
| .globl __udivmodqi4 |
| .type __udivmodqi4, @function |
| |
| __udivmodqi4: |
| sub r25, r25 ; Initialize the remainder to zero. |
| ldi r23, 9 ; Only loop 8 rounds for uint8. |
| |
| __udivmodqi4_loop: |
| adc r24, r24 |
| dec r23 |
| breq __udivmodqi4_end |
| adc r25, r25 |
| cp r25, r22 ; Compare with the divisor. |
| brcs __udivmodqi4_loop |
| sub r25, r22 ; Subtract the divisor. |
| rjmp __udivmodqi4_loop |
| |
| __udivmodqi4_end: |
| com r24 ; The uint8 quotient is returned via R24. |
| ret ; The uint8 remainder is returned via R25. |
