Commit eff10f66 authored by Damien George's avatar Damien George
Browse files

py: Implement bl/bx instructions for inline Thumb assembler.

parent 42495392
......@@ -40,6 +40,7 @@
#define SIGNED_FIT8(x) (((x) & 0xffffff80) == 0) || (((x) & 0xffffff80) == 0xffffff80)
#define SIGNED_FIT9(x) (((x) & 0xffffff00) == 0) || (((x) & 0xffffff00) == 0xffffff00)
#define SIGNED_FIT12(x) (((x) & 0xfffff800) == 0) || (((x) & 0xfffff800) == 0xfffff800)
#define SIGNED_FIT23(x) (((x) & 0xffc00000) == 0) || (((x) & 0xffc00000) == 0xffc00000)
struct _asm_thumb_t {
mp_uint_t pass;
......@@ -455,6 +456,20 @@ 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))
......
......@@ -207,6 +207,7 @@ void asm_thumb_mov_reg_local_addr(asm_thumb_t *as, uint rlo_dest, int local_num)
void asm_thumb_b_label(asm_thumb_t *as, uint label); // convenience ?
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 ?
#endif // __MICROPY_INCLUDED_PY_ASMTHUMB_H__
......@@ -336,6 +336,13 @@ STATIC void emit_inline_thumb_op(emit_inline_asm_t *emit, qstr op, mp_uint_t n_a
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);
} 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);
} 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));
} else if (op_str[0] == 'b' && op_len == 3) {
mp_uint_t cc = -1;
for (mp_uint_t i = 0; i < MP_ARRAY_SIZE(cc_name_table); i++) {
......
# test bl and bx instructions
@micropython.asm_thumb
def f(r0):
# jump over the internal functions
b(entry)
label(func1)
add(r0, 2)
bx(lr)
label(func2)
sub(r0, 1)
bx(lr)
label(entry)
bl(func1)
bl(func2)
print(f(0))
print(f(1))
# test it instruction
@micropython.asm_thumb
def f(r0, r1):
cmp(r0, r1)
it(eq)
mov(r0, 100)
print(f(0, 0), f(1, 2))
@micropython.asm_thumb
def g(r0, r1):
cmp(r0, r1)
ite(eq)
mov(r0, 100)
mov(r0, 200)
print(g(0, 0), g(0, 1))
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