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Diffstat (limited to 'contrib/llvm-project/compiler-rt/lib/builtins/avr/udivmodqi4.S')
| -rw-r--r-- | contrib/llvm-project/compiler-rt/lib/builtins/avr/udivmodqi4.S | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/contrib/llvm-project/compiler-rt/lib/builtins/avr/udivmodqi4.S b/contrib/llvm-project/compiler-rt/lib/builtins/avr/udivmodqi4.S new file mode 100644 index 000000000000..99aec3442936 --- /dev/null +++ b/contrib/llvm-project/compiler-rt/lib/builtins/avr/udivmodqi4.S @@ -0,0 +1,39 @@ +//===------------ 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. |