From 794df0f1d502bf715449ed6d36f16cf52b095d0b Mon Sep 17 00:00:00 2001
From: graham sanderson <graham.sanderson@raspberrypi.org>
Date: Sun, 17 Jan 2021 21:56:34 -0600
Subject: [PATCH] py/emitnative: Support binary ops on ARMv6M without use of
 ite instr.

---
 py/asmthumb.c   | 12 ++++++++++++
 py/asmthumb.h   |  2 ++
 py/emitnative.c | 23 +++++++++++++++++++++++
 3 files changed, 37 insertions(+)

diff --git a/py/asmthumb.c b/py/asmthumb.c
index e3558b2cf256..f7ac87fa0f93 100644
--- a/py/asmthumb.c
+++ b/py/asmthumb.c
@@ -564,6 +564,18 @@ void asm_thumb_bcc_label(asm_thumb_t *as, int cond, uint label) {
     }
 }
 
+void asm_thumb_bcc_rel9(asm_thumb_t *as, int cond, int rel) {
+    rel -= 4; // account for instruction prefetch, PC is 4 bytes ahead of this instruction
+    assert(SIGNED_FIT9(rel));
+    asm_thumb_op16(as, OP_BCC_N(cond, rel));
+}
+
+void asm_thumb_b_rel12(asm_thumb_t *as, int rel) {
+    rel -= 4; // account for instruction prefetch, PC is 4 bytes ahead of this instruction
+    assert(SIGNED_FIT12(rel));
+    asm_thumb_op16(as, OP_B_N(rel));
+}
+
 #define OP_BLX(reg) (0x4780 | ((reg) << 3))
 #define OP_SVC(arg) (0xdf00 | (arg))
 
diff --git a/py/asmthumb.h b/py/asmthumb.h
index 3c4533618665..17a0cca98c58 100644
--- a/py/asmthumb.h
+++ b/py/asmthumb.h
@@ -330,6 +330,8 @@ void asm_thumb_ldr_reg_reg_i12_optimised(asm_thumb_t *as, uint reg_dest, uint re
 void asm_thumb_b_label(asm_thumb_t *as, uint label); // convenience: picks narrow or wide branch
 void asm_thumb_bcc_label(asm_thumb_t *as, int cc, uint label); // convenience: picks narrow or wide branch
 void asm_thumb_bl_ind(asm_thumb_t *as, uint fun_id, uint reg_temp); // convenience
+void asm_thumb_bcc_rel9(asm_thumb_t *as, int cc, int rel);
+void asm_thumb_b_rel12(asm_thumb_t *as, int rel);
 
 // Holds a pointer to mp_fun_table
 #define ASM_THUMB_REG_FUN_TABLE ASM_THUMB_REG_R7
diff --git a/py/emitnative.c b/py/emitnative.c
index 8cb5de1b4af9..052a505911d2 100644
--- a/py/emitnative.c
+++ b/py/emitnative.c
@@ -2454,6 +2454,7 @@ STATIC void emit_native_binary_op(emit_t *emit, mp_binary_op_t op) {
             asm_x86_setcc_r8(emit->as, ops[op_idx], REG_RET);
             #elif N_THUMB
             asm_thumb_cmp_rlo_rlo(emit->as, REG_ARG_2, reg_rhs);
+            #if MICROPY_EMIT_THUMB_ARMV7M
             static uint16_t ops[6 + 6] = {
                 // unsigned
                 ASM_THUMB_OP_ITE_CC,
@@ -2473,6 +2474,28 @@ STATIC void emit_native_binary_op(emit_t *emit, mp_binary_op_t op) {
             asm_thumb_op16(emit->as, ops[op_idx]);
             asm_thumb_mov_rlo_i8(emit->as, REG_RET, 1);
             asm_thumb_mov_rlo_i8(emit->as, REG_RET, 0);
+            #else
+            static uint16_t ops[6 + 6] = {
+                // unsigned
+                ASM_THUMB_CC_CC,
+                ASM_THUMB_CC_HI,
+                ASM_THUMB_CC_EQ,
+                ASM_THUMB_CC_LS,
+                ASM_THUMB_CC_CS,
+                ASM_THUMB_CC_NE,
+                // signed
+                ASM_THUMB_CC_LT,
+                ASM_THUMB_CC_GT,
+                ASM_THUMB_CC_EQ,
+                ASM_THUMB_CC_LE,
+                ASM_THUMB_CC_GE,
+                ASM_THUMB_CC_NE,
+            };
+            asm_thumb_bcc_rel9(emit->as, ops[op_idx], 6);
+            asm_thumb_mov_rlo_i8(emit->as, REG_RET, 0);
+            asm_thumb_b_rel12(emit->as, 4);
+            asm_thumb_mov_rlo_i8(emit->as, REG_RET, 1);
+            #endif
             #elif N_ARM
             asm_arm_cmp_reg_reg(emit->as, REG_ARG_2, reg_rhs);
             static uint ccs[6 + 6] = {