py/asm: Remove need for dummy_data when doing initial assembler passes.

For all but the last pass the assembler only needs to count how much space
is needed for the machine code, it doesn't actually need to emit anything.
The dummy_data just uses unnecessary RAM and without it the code is not
any more complex (and code size does not increase for Thumb and Xtensa
archs).

1 files changed, 12 insertions, 8 deletions

diff --git a/py/asmthumb.c b/py/asmthumb.c
index 82a226b62..749c1e405 100644
--- a/py/asmthumb.c
+++ b/py/asmthumb.c
@@ -162,18 +162,22 @@ STATIC mp_uint_t get_label_dest(asm_thumb_t *as, uint label) {
 
 void asm_thumb_op16(asm_thumb_t *as, uint op) {
     byte *c = asm_thumb_get_cur_to_write_bytes(as, 2);
-    // little endian
-    c[0] = op;
-    c[1] = op >> 8;
+    if (c != NULL) {
+        // little endian
+        c[0] = op;
+        c[1] = op >> 8;
+    }
 }
 
 void asm_thumb_op32(asm_thumb_t *as, uint op1, uint op2) {
     byte *c = asm_thumb_get_cur_to_write_bytes(as, 4);
-    // little endian, op1 then op2
-    c[0] = op1;
-    c[1] = op1 >> 8;
-    c[2] = op2;
-    c[3] = op2 >> 8;
+    if (c != NULL) {
+        // little endian, op1 then op2
+        c[0] = op1;
+        c[1] = op1 >> 8;
+        c[2] = op2;
+        c[3] = op2 >> 8;
+    }
 }
 
 #define OP_FORMAT_4(op, rlo_dest, rlo_src) ((op) | ((rlo_src) << 3) | (rlo_dest))