diff options
Diffstat (limited to 'py/asmthumb.c')
| -rw-r--r-- | py/asmthumb.c | 16 |
1 files changed, 14 insertions, 2 deletions
diff --git a/py/asmthumb.c b/py/asmthumb.c index 91fff3955c..ba61c31f65 100644 --- a/py/asmthumb.c +++ b/py/asmthumb.c @@ -288,6 +288,19 @@ void asm_thumb_cmp_rlo_i8(asm_thumb_t *as, uint rlo, int i8) { asm_thumb_write_op16(as, OP_CMP_RLO_I8(rlo, i8)); } +#define OP_B_N(byte_offset) (0xe000 | (((byte_offset) >> 1) & 0x07ff)) + +void asm_thumb_b_n(asm_thumb_t *as, int label) { + int dest = get_label_dest(as, label); + int 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_write_op16(as, OP_B_N(rel)); + } else { + printf("asm_thumb_b_n: branch does not fit in 12 bits\n"); + } +} + #define OP_BEQ_N(byte_offset) (0xd000 | (((byte_offset) >> 1) & 0x00ff)) #define OP_BNE_N(byte_offset) (0xd100 | (((byte_offset) >> 1) & 0x00ff)) #define OP_BCS_N(byte_offset) (0xd200 | (((byte_offset) >> 1) & 0x00ff)) @@ -371,7 +384,6 @@ void asm_thumb_ite_ge(asm_thumb_t *as) { asm_thumb_write_op16(as, 0xbfac); } -#define OP_B(byte_offset) (0xe000 | (((byte_offset) >> 1) & 0x07ff)) // this could be wrong, because it should have a range of +/- 16MiB... #define OP_BW_HI(byte_offset) (0xf000 | (((byte_offset) >> 12) & 0x07ff)) #define OP_BW_LO(byte_offset) (0xb800 | (((byte_offset) >> 1) & 0x07ff)) @@ -384,7 +396,7 @@ void asm_thumb_b_label(asm_thumb_t *as, int label) { // is a backwards jump, so we know the size of the jump on the first pass // calculate rel assuming 12 bit relative jump if (SIGNED_FIT12(rel)) { - asm_thumb_write_op16(as, OP_B(rel)); + asm_thumb_write_op16(as, OP_B_N(rel)); } else { goto large_jump; } |