diff --git a/src/main/fragment/mos6502-common/pwsz1_derefidx_vbuyy=pwsz1_derefidx_vbuyy_plus_vbsm2.asm b/src/main/fragment/mos6502-common/pwsz1_derefidx_vbuyy=pwsz1_derefidx_vbuyy_plus_vbsm2.asm
new file mode 100644
index 000000000..42b4e9e05
--- /dev/null
+++ b/src/main/fragment/mos6502-common/pwsz1_derefidx_vbuyy=pwsz1_derefidx_vbuyy_plus_vbsm2.asm
@@ -0,0 +1,13 @@
+lda {m2}
+sta $ff
+clc
+adc ({z1}),y
+sta ({z1}),y
+iny
+lda $ff
+ora #$7f
+bmi !+
+lda #0
+!:
+adc ({z1}),y
+sta ({z1}),y
\ No newline at end of file