From 7d3293c45db7412be87e67ba108065cfb261af5d Mon Sep 17 00:00:00 2001
From: Walter Bright <WalterBright@users.noreply.github.com>
Date: Sat, 15 Mar 2025 15:33:30 -0700
Subject: [PATCH] carith and more branch logic (#21002)

* carith() function in exe1.c tests

* more branch logic
---
 compiler/src/dmd/backend/arm/cod3.d | 24 ++++++++++++++----------
 1 file changed, 14 insertions(+), 10 deletions(-)

diff --git a/compiler/src/dmd/backend/arm/cod3.d b/compiler/src/dmd/backend/arm/cod3.d
index d76484e31d..1060a296b3 100644
--- a/compiler/src/dmd/backend/arm/cod3.d
+++ b/compiler/src/dmd/backend/arm/cod3.d
@@ -109,7 +109,8 @@ void REGSAVE_restore(const ref REGSAVE regsave, ref CodeBuilder cdb, reg_t reg,
 
 
 // https://www.scs.stanford.edu/~zyedidia/arm64/b_cond.html
-bool isBranch(uint ins) { return (ins & ((0xFF << 24) | (1 << 4))) == ((0x54 << 24) | (0 << 4)); }
+// https://www.scs.stanford.edu/~zyedidia/arm64/bc_cond.html
+bool isBranch(uint ins) { return (ins & 0xFF00_0000) == 0x5400_0000; }
 
 enum MARS = true;
 
@@ -1496,7 +1497,7 @@ printf("offset: %lld localsize: %lld REGSIZE*2: %d\n", offset, localsize, REGSIZ
                 break;
 
             default:
-                if (0) printf("FL: %s\n", fl_str(c.IFL1));
+                if (1) printf("FL: %s\n", fl_str(c.IFL1));
                 assert(0);
         }
     }
@@ -1517,10 +1518,10 @@ printf("offset: %lld localsize: %lld REGSIZE*2: %d\n", offset, localsize, REGSIZ
 @trusted
 void jmpaddr(code* c)
 {
-    code* ci,cn,ctarg,cstart;
-    targ_size_t ad;
-
     //printf("jmpaddr()\n");
+
+    code* ci,cn,ctarg,cstart;
+    uint ad;
     cstart = c;                           /* remember start of code       */
     while (c)
     {
@@ -1538,7 +1539,7 @@ void jmpaddr(code* c)
             }
             if (!ci)
                 goto Lbackjmp;      // couldn't find it
-            c.Iop |= cast(uint)(ad >> 2) << 5;
+            c.Iop |= (ad >> 2) << 5;
             c.IFL1 = FL.unde;
         }
         if (op == LOOP && c.IFL1 == FL.code)    /* backwards refs       */
@@ -1555,7 +1556,7 @@ void jmpaddr(code* c)
                 ad += calccodsize(ci);
                 ci = code_next(ci);
             }
-            c.Iop = cast(uint)(-(ad >> 2)) << 5;
+            c.Iop = (-(ad >> 2)) << 5;
             c.IFL1 = FL.unde;
         }
         c = code_next(c);
@@ -1605,8 +1606,7 @@ uint calccodsize(code* c)
 @trusted
 uint codout(int seg, code* c, Barray!ubyte* disasmBuf, ref targ_size_t framehandleroffset)
 {
-    code* cn;
-    uint flags;
+    //printf("codout()\n");
 
     debug
     if (debugc) printf("codout(%p), Coffset = x%llx\n",c,cast(ulong)Offset(seg));
@@ -1618,6 +1618,9 @@ uint codout(int seg, code* c, Barray!ubyte* disasmBuf, ref targ_size_t framehand
     ggen.framehandleroffset = framehandleroffset;
     ggen.disasmBuf = disasmBuf;
 
+    code* cn;
+    uint flags;
+
     for (; c; c = code_next(c))
     {
         debug
@@ -1681,7 +1684,8 @@ uint codout(int seg, code* c, Barray!ubyte* disasmBuf, ref targ_size_t framehand
         if (ggen.available() < 4)
             ggen.flush();
 
-        if (c.IFL1 == FL.block)  // branch to a block - compute offset
+        if (isBranch(op) && c.IFL1 == FL.block)
+
         {
             ggen.flush();
             int ad = cast(int)(c.IEV1.Vblock.Boffset - ggen.offset);