diff options
| author | Alessandro Gatti <a.gatti@frob.it> | 2025-01-24 00:20:39 +0100 |
|---|---|---|
| committer | Damien George <damien@micropython.org> | 2025-01-26 23:42:36 +1100 |
| commit | 40585eaa8f1b603f0094b73764e8ce5623812ecf (patch) | |
| tree | bb6e210d652e9184ab02720697b063b2a9f56661 /py/emitnative.c | |
| parent | bfc0d7b0b97cbf52db892775b0f371dd06d2ba08 (diff) | |
py/emitnative: Emit shorter exception handler entry code on RV32.
This commit improves the RV32 code sequence that is emitted if a
function needs to set up an exception handler as its prologue.
The old code would clear a temporary register and then copy that value
to places that needed to be initialised with zero values. On RV32
there's a dedicated register that's hardwired to be equal to zero, which
allows us to bypass the extra register clear and use the zero register
to initialise values.
Signed-off-by: Alessandro Gatti <a.gatti@frob.it>
Diffstat (limited to 'py/emitnative.c')
| -rw-r--r-- | py/emitnative.c | 15 |
1 files changed, 10 insertions, 5 deletions
diff --git a/py/emitnative.c b/py/emitnative.c index 7d856e13f..f846e8bb4 100644 --- a/py/emitnative.c +++ b/py/emitnative.c @@ -288,6 +288,11 @@ struct _emit_t { ASM_T *as; }; +#ifndef REG_ZERO +#define REG_ZERO REG_TEMP0 +#define ASM_CLR_REG(state, rd) ASM_XOR_REG_REG(state, rd, rd) +#endif + static void emit_load_reg_with_object(emit_t *emit, int reg, mp_obj_t obj); static void emit_native_global_exc_entry(emit_t *emit); static void emit_native_global_exc_exit(emit_t *emit); @@ -1200,12 +1205,12 @@ static void emit_native_global_exc_entry(emit_t *emit) { ASM_JUMP_IF_REG_ZERO(emit->as, REG_RET, start_label, true); } else { // Clear the unwind state - ASM_XOR_REG_REG(emit->as, REG_TEMP0, REG_TEMP0); - ASM_MOV_LOCAL_REG(emit->as, LOCAL_IDX_EXC_HANDLER_UNWIND(emit), REG_TEMP0); + ASM_CLR_REG(emit->as, REG_ZERO); + ASM_MOV_LOCAL_REG(emit->as, LOCAL_IDX_EXC_HANDLER_UNWIND(emit), REG_ZERO); // clear nlr.ret_val, because it's passed to mp_native_raise regardless // of whether there was an exception or not - ASM_MOV_LOCAL_REG(emit->as, LOCAL_IDX_EXC_VAL(emit), REG_TEMP0); + ASM_MOV_LOCAL_REG(emit->as, LOCAL_IDX_EXC_VAL(emit), REG_ZERO); // Put PC of start code block into REG_LOCAL_1 ASM_MOV_REG_PCREL(emit->as, REG_LOCAL_1, start_label); @@ -1221,8 +1226,8 @@ static void emit_native_global_exc_entry(emit_t *emit) { ASM_JUMP_IF_REG_NONZERO(emit->as, REG_RET, global_except_label, true); // Clear PC of current code block, and jump there to resume execution - ASM_XOR_REG_REG(emit->as, REG_TEMP0, REG_TEMP0); - ASM_MOV_LOCAL_REG(emit->as, LOCAL_IDX_EXC_HANDLER_PC(emit), REG_TEMP0); + ASM_CLR_REG(emit->as, REG_ZERO); + ASM_MOV_LOCAL_REG(emit->as, LOCAL_IDX_EXC_HANDLER_PC(emit), REG_ZERO); ASM_JUMP_REG(emit->as, REG_LOCAL_1); // Global exception handler: check for valid exception handler |