diff --git a/Ghidra/Processors/6502/data/languages/65c02.slaspec b/Ghidra/Processors/6502/data/languages/65c02.slaspec
index e3d178f0e1..45e50d80f5 100644
--- a/Ghidra/Processors/6502/data/languages/65c02.slaspec
+++ b/Ghidra/Processors/6502/data/languages/65c02.slaspec
@@ -163,7 +163,7 @@ ADDRIX: (imm16,X) is X; imm16     { addr:2 = imm16 + zext(X); tmp:2 = *:2 addr;
 :SBC ZIOP                      is (cc=2 & aaa=7) ... & ZIOP
 {
     local op1 = ZIOP;
-    local result = A - op1 - C;
+    local result = A - op1 - (1 - C);
 
     subtraction_flags1(A, op1, result);
     A = result;