py/asmthumb: Fix T3 encoding of conditional branches.

This commit fixes the encoding of conditional branch opcodes emitted for
ARMv7-M targets, when the emitter decides to use the T3 encoding for
said operation.

Fields J1 and J2 are now present in the generated opcode word, along
with correcting some minor issues in bitmasks and shifts computation.

This fixes #17940.

Signed-off-by: Alessandro Gatti <a.gatti@frob.it>

1 files changed, 2 insertions, 3 deletions

diff --git a/py/asmthumb.c b/py/asmthumb.c
index 93860d2fd..58cc7aea8 100644
--- a/py/asmthumb.c
+++ b/py/asmthumb.c
@@ -267,9 +267,8 @@ bool asm_thumb_b_n_label(asm_thumb_t *as, uint label) {
 
 #define OP_BCC_N(cond, byte_offset) (0xd000 | ((cond) << 8) | (((byte_offset) >> 1) & 0x00ff))
 
-// all these bit-arithmetic operations need coverage testing!
-#define OP_BCC_W_HI(cond, byte_offset) (0xf000 | ((cond) << 6) | (((byte_offset) >> 10) & 0x0400) | (((byte_offset) >> 14) & 0x003f))
-#define OP_BCC_W_LO(byte_offset) (0x8000 | ((byte_offset) & 0x2000) | (((byte_offset) >> 1) & 0x0fff))
+#define OP_BCC_W_HI(cond, byte_offset) (0xf000 | ((cond) << 6) | (((byte_offset) >> 10) & 0x0400) | (((byte_offset) >> 12) & 0x003f))
+#define OP_BCC_W_LO(byte_offset) (0x8000 | (((byte_offset) >> 5) & 0x2000) | (((byte_offset) >> 8) & 0x0800) | (((byte_offset) >> 1) & 0x07ff))
 
 bool asm_thumb_bcc_nw_label(asm_thumb_t *as, int cond, uint label, bool wide) {
     mp_uint_t dest = get_label_dest(as, label);