diff --git a/Asm65/OpDef.cs b/Asm65/OpDef.cs
index eb1ba92..48d7c38 100644
--- a/Asm65/OpDef.cs
+++ b/Asm65/OpDef.cs
@@ -939,8 +939,12 @@ namespace Asm65 {
             Mnemonic = OpName.BRK,
             Effect = FlowEffect.NoCont,
             BaseMemEffect = MemoryEffect.None,
-            // On 6502/65C02 this also affects the 'B' flag, which overlaps with X.  Nobody
-            // really cares though.  On 6502 this doesn't clear the 'D' flag.
+            // On 6502 this doesn't clear the 'D' flag.  Easier to explain that in text than
+            // create a separate definition.
+            //
+            // The processor status flags have the 'B' flag set on 6502/65C02/65816 emu mode
+            // when pushed onto the stack, but it doesn't affect the actual processor status
+            // flag in the code executed next.
             //
             // We don't set a StatusFlagUpdater because the flags are only changed for the
             // software break handler function.  If we could actually track this into that,
diff --git a/Asm65/OpDescription.cs b/Asm65/OpDescription.cs
index 349157b..b88576f 100644
--- a/Asm65/OpDescription.cs
+++ b/Asm65/OpDescription.cs
@@ -286,7 +286,12 @@ namespace Asm65 {
             { OpName.BRK,
                 "Pushes state onto the stack, and jumps to the software break vector at " +
                 "$fffe-ffff.  While this is technically a single-byte instruction, the " +
-                "program counter pushed onto the stack is incremented by two."
+                "program counter pushed onto the stack is incremented by two.  The interrupt " +
+                "flag is set, and on 65C02/65816 the D flag is cleared. " +
+                "On 6502, 65C02, and 65816 in emulation mode, the status flags pushed onto " +
+                "the stack will have the 'B' flag (which overlaps the 'X' flag) set so the " +
+                "interrupt handler can tell the difference between hardware and software " +
+                "interrupts."
             },
             { OpName.BRL,
                 "Branches to a long relative address."