The radio hard-froze (needs battery pull) the instant it processed an incoming
DMR frame — repeater reply, or noise on a DMR channel. FM and DMR TX-without-a-
listening-repeater were fine. Cause: codec_interface.c invoked the AMBE codec
through hand-written inline assembler with no operands and no clobber list,
branching (BL) to an absolute address. That code's correctness depends entirely
on a specific compiler's register allocation; modern GNU toolchains (both ARM
GCC 10 and 14) miscompile it, corrupting state on the first codec call.
Port the official R20260504 (git ebd7100) rework: replace all five inline-asm
calls (2x decode, 2x encode, 1x ECC) with C function-pointer calls. Each call
reproduces the exact register/stack layout the assembler set up (AAPCS: args
1-4 -> r0-r3, args 5+ -> stack) and sets the Thumb bit on the target address.
Also drop the trailing semicolons from the AMBE_* address macros in codec.h so
they can be used in C expressions.
Builds cleanly with the GCC 14.2 Docker toolchain (no STM32CubeIDE needed) and
DMR RX/TX now works on the radio.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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