AVR: Add __negdi2_r10 to libgcc.

AVR target gets a new libgcc function for 64-bit negation to simplify existing operations.

By Georg-Johann Lay July 25, 2026 committed

This patch adds the __negdi2_r10 function to libgcc for the AVR target. It also tidies up some 64-bit negation operations, using the new function where applicable in __divdi3_moddi3 and __mulQ64_work. This improves the handling of 64-bit arithmetic on AVR.

In Details

The AVR target's libgcc library gains a new function __negdi2_r10 for efficient 64-bit negation. This function is then integrated into existing 64-bit arithmetic routines like __divdi3_moddi3 and __mulQ64_work to streamline their operation.

For Context

libgcc: GCC's runtime library, providing support functions for operations not directly handled by the target architecture's instruction set, such as integer division on some platforms, or floating-point operations.
AVR: A family of microcontrollers developed by Atmel (now Microchip Technology). GCC has support for generating code for these embedded systems.

Filed Under: avrlibgcc64-bit arithmetic

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