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py: Make inline assembler raise exception when branch not in range.

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Addresses issue #1132.
This commit is contained in:
Damien George 2015-02-25 15:45:55 +00:00
parent 11aa6ba456
commit 534574348e
3 changed files with 41 additions and 29 deletions
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39
py/asmthumb.c
View File

@ -293,27 +293,44 @@ void asm_thumb_mov_reg_i16(asm_thumb_t *as, uint mov_op, uint reg_dest, int i16_
#define OP_B_N(byte_offset) (0xe000 | (((byte_offset) >> 1) & 0x07ff))
void asm_thumb_b_n(asm_thumb_t *as, uint label) {
bool asm_thumb_b_n_label(asm_thumb_t *as, uint label) {
mp_uint_t dest = get_label_dest(as, label);
mp_int_t rel = dest - as->code_offset;
rel -= 4; // account for instruction prefetch, PC is 4 bytes ahead of this instruction
if (SIGNED_FIT12(rel)) {
asm_thumb_op16(as, OP_B_N(rel));
return true;
} else {
printf("asm_thumb_b_n: branch does not fit in 12 bits\n");
return false;
}
}
#define OP_BCC_N(cond, byte_offset) (0xd000 | ((cond) << 8) | (((byte_offset) >> 1) & 0x00ff))
void asm_thumb_bcc_n(asm_thumb_t *as, int cond, uint label) {
bool asm_thumb_bcc_n_label(asm_thumb_t *as, int cond, uint label) {
mp_uint_t dest = get_label_dest(as, label);
mp_int_t rel = dest - as->code_offset;
rel -= 4; // account for instruction prefetch, PC is 4 bytes ahead of this instruction
if (SIGNED_FIT9(rel)) {
asm_thumb_op16(as, OP_BCC_N(cond, rel));
return true;
} else {
printf("asm_thumb_bcc_n: branch does not fit in 9 bits\n");
return false;
}
}
#define OP_BL_HI(byte_offset) (0xf000 | (((byte_offset) >> 12) & 0x07ff))
#define OP_BL_LO(byte_offset) (0xf800 | (((byte_offset) >> 1) & 0x07ff))
bool asm_thumb_bl_label(asm_thumb_t *as, uint label) {
mp_uint_t dest = get_label_dest(as, label);
mp_int_t rel = dest - as->code_offset;
rel -= 4; // account for instruction prefetch, PC is 4 bytes ahead of this instruction
if (SIGNED_FIT23(rel)) {
asm_thumb_op32(as, OP_BL_HI(rel), OP_BL_LO(rel));
return true;
} else {
return false;
}
}
@ -422,20 +439,6 @@ void asm_thumb_bcc_label(asm_thumb_t *as, int cond, uint label) {
}
}
#define OP_BL_HI(byte_offset) (0xf000 | (((byte_offset) >> 12) & 0x07ff))
#define OP_BL_LO(byte_offset) (0xf800 | (((byte_offset) >> 1) & 0x07ff))
void asm_thumb_bl(asm_thumb_t *as, uint label) {
mp_uint_t dest = get_label_dest(as, label);
mp_int_t rel = dest - as->code_offset;
rel -= 4; // account for instruction prefetch, PC is 4 bytes ahead of this instruction
if (SIGNED_FIT23(rel)) {
asm_thumb_op32(as, OP_BL_HI(rel), OP_BL_LO(rel));
} else {
printf("asm_thumb_bl: branch does not fit in 23 bits\n");
}
}
#define OP_BLX(reg) (0x4780 | ((reg) << 3))
#define OP_SVC(arg) (0xdf00 | (arg))

11
py/asmthumb.h
View File

@ -214,8 +214,10 @@ static inline void asm_thumb_ldrh_rlo_rlo_i5(asm_thumb_t *as, uint rlo_dest, uin
void asm_thumb_mov_reg_reg(asm_thumb_t *as, uint reg_dest, uint reg_src);
void asm_thumb_mov_reg_i16(asm_thumb_t *as, uint mov_op, uint reg_dest, int i16_src);
void asm_thumb_b_n(asm_thumb_t *as, uint label);
void asm_thumb_bcc_n(asm_thumb_t *as, int cond, uint label);
// these return true if the destination is in range, false otherwise
bool asm_thumb_b_n_label(asm_thumb_t *as, uint label);
bool asm_thumb_bcc_n_label(asm_thumb_t *as, int cond, uint label);
bool asm_thumb_bl_label(asm_thumb_t *as, uint label);
void asm_thumb_mov_reg_i32(asm_thumb_t *as, uint reg_dest, mp_uint_t i32_src); // convenience
void asm_thumb_mov_reg_i32_optimised(asm_thumb_t *as, uint reg_dest, int i32_src); // convenience
@ -224,9 +226,8 @@ void asm_thumb_mov_local_reg(asm_thumb_t *as, int local_num_dest, uint rlo_src);
void asm_thumb_mov_reg_local(asm_thumb_t *as, uint rlo_dest, int local_num); // convenience
void asm_thumb_mov_reg_local_addr(asm_thumb_t *as, uint rlo_dest, int local_num); // convenience
void asm_thumb_b_label(asm_thumb_t *as, uint label); // convenience ?
void asm_thumb_b_label(asm_thumb_t *as, uint label); // convenience: picks narrow or wide branch
void asm_thumb_bcc_label(asm_thumb_t *as, int cc, uint label); // convenience: picks narrow or wide branch
void asm_thumb_bl(asm_thumb_t *as, uint label);
void asm_thumb_bl_ind(asm_thumb_t *as, void *fun_ptr, uint fun_id, uint reg_temp); // convenience ?
void asm_thumb_bl_ind(asm_thumb_t *as, void *fun_ptr, uint fun_id, uint reg_temp); // convenience
#endif // __MICROPY_INCLUDED_PY_ASMTHUMB_H__

20
py/emitinlinethumb.c
View File

@ -367,12 +367,14 @@ STATIC void emit_inline_thumb_op(emit_inline_asm_t *emit, qstr op, mp_uint_t n_a
} else if (n_args == 1) {
if (strcmp(op_str, "b") == 0) {
int label_num = get_arg_label(emit, op_str, pn_args[0]);
// TODO check that this succeeded, ie branch was within range
asm_thumb_b_n(emit->as, label_num);
if (!asm_thumb_b_n_label(emit->as, label_num)) {
goto branch_not_in_range;
}
} else if (strcmp(op_str, "bl") == 0) {
int label_num = get_arg_label(emit, op_str, pn_args[0]);
// TODO check that this succeeded, ie branch was within range
asm_thumb_bl(emit->as, label_num);
if (!asm_thumb_bl_label(emit->as, label_num)) {
goto branch_not_in_range;
}
} else if (strcmp(op_str, "bx") == 0) {
mp_uint_t r = get_arg_reg(emit, op_str, pn_args[0], 15);
asm_thumb_op16(emit->as, 0x4700 | (r << 3));
@ -387,8 +389,9 @@ STATIC void emit_inline_thumb_op(emit_inline_asm_t *emit, qstr op, mp_uint_t n_a
goto unknown_op;
}
int label_num = get_arg_label(emit, op_str, pn_args[0]);
// TODO check that this succeeded, ie branch was within range
asm_thumb_bcc_n(emit->as, cc, label_num);
if (!asm_thumb_bcc_n_label(emit->as, cc, label_num)) {
goto branch_not_in_range;
}
} else if (op_str[0] == 'i' && op_str[1] == 't') {
const char *arg_str = get_arg_str(pn_args[0]);
mp_uint_t cc = -1;
@ -608,6 +611,11 @@ STATIC void emit_inline_thumb_op(emit_inline_asm_t *emit, qstr op, mp_uint_t n_a
unknown_op:
emit_inline_thumb_error_exc(emit, mp_obj_new_exception_msg_varg(&mp_type_SyntaxError, "unsupported Thumb instruction '%s' with %d arguments", op_str, n_args));
return;
branch_not_in_range:
emit_inline_thumb_error_msg(emit, "branch not in range");
return;
}
const emit_inline_asm_method_table_t emit_inline_thumb_method_table = {