Removed clz.c workaround; use riscv32-unknown-elf toolchain (#538)

bsp/clz.c provided a weak __clzsi2 fallback to work around the missing
rv32 multilib in the riscv-collab riscv64-unknown-elf toolchain.  Since
cmake/riscv32-unknown-elf-rv32imc.cmake now uses the dedicated riscv32-
unknown-elf-gcc toolchain (riscv-collab riscv32-elf release), which ships
a native rv32/ilp32 libgcc with all required helpers, the workaround is
no longer needed.

Remove bsp/clz.c and its entry in CMakeLists.txt.

Co-authored-by: Copilot <[email protected]>

2 files changed, 0 insertions, 30 deletions

diff --git a/ports/risc-v32/gnu/example_build/core_v_mcu/CMakeLists.txt b/ports/risc-v32/gnu/example_build/core_v_mcu/CMakeLists.txt
index 6946b347..662914d1 100644
--- a/ports/risc-v32/gnu/example_build/core_v_mcu/CMakeLists.txt
+++ b/ports/risc-v32/gnu/example_build/core_v_mcu/CMakeLists.txt
@@ -21,7 +21,6 @@ set(SRCS
     ${CORE_V_MCU_DIR}/crt0.S
     ${CORE_V_MCU_DIR}/vectors.S
     ${CORE_V_MCU_DIR}/tx_initialize_low_level.S
-    ${CORE_V_MCU_DIR}/bsp/clz.c
     ${CORE_V_MCU_DIR}/bsp/irq.c
     ${CORE_V_MCU_DIR}/bsp/timer_irq.c
     ${CORE_V_MCU_DIR}/bsp/fll.c
diff --git a/ports/risc-v32/gnu/example_build/core_v_mcu/bsp/clz.c b/ports/risc-v32/gnu/example_build/core_v_mcu/bsp/clz.c
deleted file mode 100644
index ef3cb23b..00000000
--- a/ports/risc-v32/gnu/example_build/core_v_mcu/bsp/clz.c
+++ /dev/null
@@ -1,29 +0,0 @@
-/* clz.c — portable fallback for __clzsi2 (count leading zeros, 32-bit)
- *
- * The riscv-collab bare-metal toolchain (riscv64-unknown-elf from /opt/riscv)
- * is built without multilib and does not ship an rv32/ilp32 libgcc.  As a
- * result __clzsi2, which GCC emits for __builtin_clz() on targets without a
- * hardware CLZ instruction, is missing at link time.
- *
- * This file provides a weak definition so that the build is self-contained
- * with any RISC-V bare-metal toolchain.  When a toolchain does ship the symbol
- * in libgcc (e.g. the Ubuntu gcc-riscv64-unknown-elf package), the libgcc copy
- * will take precedence over this weak one.
- */
-
-#include <stdint.h>
-
-__attribute__((weak))
-int __clzsi2(uint32_t x)
-{
-    if (x == 0U)
-        return 32;
-
-    int n = 0;
-    if ((x & 0xFFFF0000U) == 0U) { n += 16; x <<= 16; }
-    if ((x & 0xFF000000U) == 0U) { n +=  8; x <<=  8; }
-    if ((x & 0xF0000000U) == 0U) { n +=  4; x <<=  4; }
-    if ((x & 0xC0000000U) == 0U) { n +=  2; x <<=  2; }
-    if ((x & 0x80000000U) == 0U) { n +=  1; }
-    return n;
-}