58 lines
1.5 KiB
ArmAsm
58 lines
1.5 KiB
ArmAsm
//===------------- divmodhi4.S - sint16 div & mod -------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// As described at
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// https://gcc.gnu.org/wiki/avr-gcc#Exceptions_to_the_Calling_Convention, the
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// prototype is `struct {sint16, sint16} __divmodhi4(sint16, sint16)`.
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// The sint16 quotient is returned via R23:R22, and the sint16 remainder is
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// returned via R25:R24, while registers R21/R26/27/Rtmp and bit T in SREG
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// are clobbered.
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//
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//===----------------------------------------------------------------------===//
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.text
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.align 2
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#ifdef __AVR_TINY__
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.set __tmp_reg__, 16
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#else
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.set __tmp_reg__, 0
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#endif
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.globl __divmodhi4
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.type __divmodhi4, @function
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__divmodhi4:
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bst r25, 7
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mov __tmp_reg__, r23
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brtc __divmodhi4_a
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com __tmp_reg__
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rcall __divmodhi4_b
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__divmodhi4_a:
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sbrc r23, 7
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rcall __divmodhi4_c
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rcall __udivmodhi4 ; Call __udivmodhi4 to do real calculation.
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sbrc __tmp_reg__, 7
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rcall __divmodhi4_c
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brtc __divmodhi4_exit
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__divmodhi4_b:
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com r25
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neg r24
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sbci r25, 255
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ret ; Return quotient via R23:R22 and remainder via R25:R24.
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__divmodhi4_c:
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com r23
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neg r22
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sbci r23, 255
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__divmodhi4_exit:
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ret ; Return quotient via R23:R22 and remainder via R25:r24.
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