py/emitinlinethumb: Make ARMv7-M instruction use dynamically selectable.

This follows on from a5324a1074 and allows
mpy-cross to dynamically select whether ARMv7-M instructions are supported
in @micropython.asm_thumb functions.

The config option MICROPY_EMIT_INLINE_THUMB_ARMV7M is no longer needed, it
is now controlled by MICROPY_EMIT_THUMB_ARMV7M.

Signed-off-by: Damien George <damien@micropython.org>

mpy-cross/mpconfigport.h

@@ -42,7 +42,6 @@
 #define MICROPY_EMIT_X86            (1)
 #define MICROPY_EMIT_THUMB          (1)
 #define MICROPY_EMIT_INLINE_THUMB   (1)
-#define MICROPY_EMIT_INLINE_THUMB_ARMV7M (1)
 #define MICROPY_EMIT_INLINE_THUMB_FLOAT (1)
 #define MICROPY_EMIT_ARM            (1)
 #define MICROPY_EMIT_XTENSA         (1)

ports/rp2/mpconfigport.h

@@ -55,7 +55,6 @@
 #define MICROPY_EMIT_THUMB_ARMV7M               (0)
 #define MICROPY_EMIT_INLINE_THUMB               (1)
 #define MICROPY_EMIT_INLINE_THUMB_FLOAT         (0)
-#define MICROPY_EMIT_INLINE_THUMB_ARMV7M        (0)
 
 // Optimisations
 #define MICROPY_OPT_COMPUTED_GOTO               (1)

py/emitinlinethumb.c

@@ -423,7 +423,7 @@ STATIC const format_vfp_op_t format_vfp_op_table[] = {
 #endif
 
 // shorthand alias for whether we allow ARMv7-M instructions
-#define ARMV7M MICROPY_EMIT_INLINE_THUMB_ARMV7M
+#define ARMV7M asm_thumb_allow_armv7m(&emit->as)
 
 STATIC void emit_inline_thumb_op(emit_inline_asm_t *emit, qstr op, mp_uint_t n_args, mp_parse_node_t *pn_args) {
     // TODO perhaps make two tables:
@@ -715,24 +715,23 @@ STATIC void emit_inline_thumb_op(emit_inline_asm_t *emit, qstr op, mp_uint_t n_a
             } else if (op == MP_QSTR_sub) {
                 op_code = ASM_THUMB_FORMAT_3_SUB;
                 goto op_format_3;
-            #if ARMV7M
-            } else if (op == MP_QSTR_movw) {
+            } else if (ARMV7M && op == MP_QSTR_movw) {
                 op_code = ASM_THUMB_OP_MOVW;
                 mp_uint_t reg_dest;
             op_movw_movt:
                 reg_dest = get_arg_reg(emit, op_str, pn_args[0], 15);
                 int i_src = get_arg_i(emit, op_str, pn_args[1], 0xffff);
                 asm_thumb_mov_reg_i16(&emit->as, op_code, reg_dest, i_src);
-            } else if (op == MP_QSTR_movt) {
+            } else if (ARMV7M && op == MP_QSTR_movt) {
                 op_code = ASM_THUMB_OP_MOVT;
                 goto op_movw_movt;
-            } else if (op == MP_QSTR_movwt) {
+            } else if (ARMV7M && op == MP_QSTR_movwt) {
                 // this is a convenience instruction
                 mp_uint_t reg_dest = get_arg_reg(emit, op_str, pn_args[0], 15);
                 uint32_t i_src = get_arg_i(emit, op_str, pn_args[1], 0xffffffff);
                 asm_thumb_mov_reg_i16(&emit->as, ASM_THUMB_OP_MOVW, reg_dest, i_src & 0xffff);
                 asm_thumb_mov_reg_i16(&emit->as, ASM_THUMB_OP_MOVT, reg_dest, (i_src >> 16) & 0xffff);
-            } else if (op == MP_QSTR_ldrex) {
+            } else if (ARMV7M && op == MP_QSTR_ldrex) {
                 mp_uint_t r_dest = get_arg_reg(emit, op_str, pn_args[0], 15);
                 mp_parse_node_t pn_base, pn_offset;
                 if (get_arg_addr(emit, op_str, pn_args[1], &pn_base, &pn_offset)) {
@@ -740,7 +739,6 @@ STATIC void emit_inline_thumb_op(emit_inline_asm_t *emit, qstr op, mp_uint_t n_a
                     mp_uint_t i8 = get_arg_i(emit, op_str, pn_offset, 0xff) >> 2;
                     asm_thumb_op32(&emit->as, 0xe850 | r_base, 0x0f00 | (r_dest << 12) | i8);
                 }
-            #endif
             } else {
                 // search table for ldr/str instructions
                 for (mp_uint_t i = 0; i < MP_ARRAY_SIZE(format_9_10_op_table); i++) {

py/mpconfig.h

@@ -361,11 +361,6 @@
 #define MICROPY_EMIT_INLINE_THUMB (0)
 #endif
 
-// Whether to enable ARMv7-M instruction support in the Thumb2 inline assembler
-#ifndef MICROPY_EMIT_INLINE_THUMB_ARMV7M
-#define MICROPY_EMIT_INLINE_THUMB_ARMV7M (1)
-#endif
-
 // Whether to enable float support in the Thumb2 inline assembler
 #ifndef MICROPY_EMIT_INLINE_THUMB_FLOAT
 #define MICROPY_EMIT_INLINE_THUMB_FLOAT (1)