diff --git a/src/main/fragment/mos6502-common/vwsm1=vwsm1_plus_pbuz2_derefidx_vbuyy.asm b/src/main/fragment/mos6502-common/vwsm1=vwsm1_plus_pbuz2_derefidx_vbuyy.asm
new file mode 100644
index 000000000..b5215c0d0
--- /dev/null
+++ b/src/main/fragment/mos6502-common/vwsm1=vwsm1_plus_pbuz2_derefidx_vbuyy.asm
@@ -0,0 +1,7 @@
+clc
+lda {m1}
+adc ({z2}),y
+sta {m1}
+bcc !+
+inc {m1}+1
+!:
\ No newline at end of file
diff --git a/src/main/fragment/mos6502-common/vwsm1=vwsm2_plus_pbum3_derefidx_vbuxx.asm b/src/main/fragment/mos6502-common/vwsm1=vwsm2_plus_pbum3_derefidx_vbuxx.asm
deleted file mode 100644
index 2454b4272..000000000
--- a/src/main/fragment/mos6502-common/vwsm1=vwsm2_plus_pbum3_derefidx_vbuxx.asm
+++ /dev/null
@@ -1,7 +0,0 @@
-clc
-lda {m2}
-adc {m3},x
-sta {m1}
-lda {m2}+1
-adc {m3}+1,x
-sta {m1}+1
diff --git a/src/main/fragment/mos6502-common/vwsm1=vwsm2_plus_pbum3_derefidx_vbuyy.asm b/src/main/fragment/mos6502-common/vwsm1=vwsm2_plus_pbum3_derefidx_vbuyy.asm
deleted file mode 100644
index 9bb3d25dc..000000000
--- a/src/main/fragment/mos6502-common/vwsm1=vwsm2_plus_pbum3_derefidx_vbuyy.asm
+++ /dev/null
@@ -1,7 +0,0 @@
-clc
-lda {m2}
-adc {m3},y
-sta {m1}
-lda {m2}+1
-adc {m3}+1,y
-sta {m1}+1
diff --git a/src/main/fragment/mos6502-common/vwsm1=vwsm2_plus_pbuz3_derefidx_vbuyy.asm b/src/main/fragment/mos6502-common/vwsm1=vwsm2_plus_pbuz3_derefidx_vbuyy.asm
new file mode 100644
index 000000000..f3199f3fc
--- /dev/null
+++ b/src/main/fragment/mos6502-common/vwsm1=vwsm2_plus_pbuz3_derefidx_vbuyy.asm
@@ -0,0 +1,7 @@
+clc
+lda {m2}
+adc ({z3}),y
+sta {m1}
+bcc !+
+inc {m2}+1
+!:
\ No newline at end of file
diff --git a/src/test/ref/atoi-1.asm b/src/test/ref/atoi-1.asm
index 7023edaed..545f8653e 100644
--- a/src/test/ref/atoi-1.asm
+++ b/src/test/ref/atoi-1.asm
@@ -509,7 +509,13 @@ atoi: {
     asl.z __3
     rol.z __3+1
     // res * 10 + str[i]
-    .assert "Missing ASM fragment Fragment not found vwsz1=vwsz1_plus_pbuz2_derefidx_vbuyy. Attempted variations vwsz1=vwsz1_plus_pbuz2_derefidx_vbuyy ", 0, 1
+    clc
+    lda.z __4
+    adc (str),y
+    sta.z __4
+    bcc !+
+    inc.z __4+1
+  !:
     // res = res * 10 + str[i] - '0'
     sec
     lda.z res
diff --git a/src/test/ref/atoi-1.log b/src/test/ref/atoi-1.log
index eafcbd9c2..29d08548b 100644
--- a/src/test/ref/atoi-1.log
+++ b/src/test/ref/atoi-1.log
@@ -4277,14 +4277,14 @@ atoi: {
     rol
     sta.z __3+1
     // [131] (signed word~) atoi::$4 ← (signed word~) atoi::$3 + *((to_nomodify byte*) atoi::str#2 + (byte) atoi::i#4) -- vwsz1=vwsz2_plus_pbuz3_derefidx_vbuz4 
-    ldx.z i
+    ldy.z i
     clc
     lda.z __3
-    adc.z str,x
+    adc (str),y
     sta.z __4
-    lda.z __3+1
-    adc.z str+1,x
-    sta.z __4+1
+    bcc !+
+    inc.z __3+1
+  !:
     // [132] (signed word) atoi::res#1 ← (signed word~) atoi::$4 - (byte) '0' -- vwsz1=vwsz2_minus_vbuc1 
     sec
     lda.z __4
@@ -4533,29 +4533,29 @@ Uplift Scope [printf_format_string]
 Uplift Scope [printf_cls] 
 Uplift Scope [main] 
 
-Uplifting [memcpy] best 24392 combination zp[2]:12 [ memcpy::src#2 memcpy::src#1 ] zp[2]:14 [ memcpy::dst#2 memcpy::dst#1 ] 
-Uplifting [memset] best 24286 combination zp[2]:10 [ memset::dst#2 memset::dst#4 memset::dst#1 ] zp[2]:48 [ memset::end#0 ] reg byte x [ memset::c#4 ] zp[2]:5 [ memset::num#2 ] zp[2]:7 [ memset::str#3 ] 
-Uplifting [utoa_append] best 23683 combination zp[2]:24 [ utoa_append::value#2 utoa_append::value#0 utoa_append::value#1 ] reg byte x [ utoa_append::digit#2 utoa_append::digit#1 ] zp[2]:59 [ utoa_append::sub#0 ] zp[2]:61 [ utoa_append::return#0 ] zp[2]:57 [ utoa_append::buffer#0 ] 
-Uplifting [printf_ln] best 23683 combination zp[2]:42 [ printf_ln::$0 ] zp[2]:44 [ printf_ln::$1 ] 
-Uplifting [printf_char] best 23647 combination zp[2]:46 [ printf_char::$6 ] reg byte a [ printf_char::ch#3 printf_char::ch#2 printf_char::ch#1 ] 
-Uplifting [printf_str] best 23527 combination zp[2]:2 [ printf_str::str#4 printf_str::str#6 printf_str::str#0 ] reg byte a [ printf_str::ch#0 ] 
-Uplifting [] best 23527 combination zp[2]:35 [ printf_cursor_ptr ] zp[1]:34 [ printf_cursor_y ] zp[1]:33 [ printf_cursor_x ] mem[12] [ printf_buffer ] 
-Uplifting [utoa] best 23393 combination zp[2]:22 [ utoa::buffer#11 utoa::buffer#14 utoa::buffer#4 ] zp[2]:19 [ utoa::value#2 utoa::value#6 utoa::value#1 utoa::value#0 ] zp[1]:18 [ utoa::digit#2 utoa::digit#1 ] reg byte a [ utoa::$10 ] reg byte x [ utoa::started#2 utoa::started#4 ] zp[2]:55 [ utoa::digit_value#0 ] reg byte a [ utoa::$11 ] zp[2]:52 [ utoa::buffer#3 ] 
-Uplifting [atoi] best 23190 combination reg byte y [ atoi::i#4 atoi::i#2 ] zp[2]:31 [ atoi::return#2 atoi::return#0 atoi::res#2 atoi::res#1 ] zp[2]:63 [ atoi::$8 ] zp[2]:65 [ atoi::$9 ] zp[2]:67 [ atoi::$3 ] zp[2]:69 [ atoi::$4 ] reg byte x [ atoi::negative#2 ] zp[2]:27 [ atoi::str#2 ] zp[2]:37 [ atoi::return#3 ] zp[2]:39 [ atoi::return#4 ] 
-Uplifting [printf_number_buffer] best 23181 combination reg byte a [ printf_number_buffer::buffer_sign#0 ] 
-Uplifting [printf_sint] best 23181 combination zp[2]:16 [ printf_sint::value#5 printf_sint::value#0 printf_sint::value#3 printf_sint::value#1 printf_sint::value#2 ] 
-Uplifting [RADIX] best 23181 combination 
-Uplifting [printf_format_number] best 23181 combination 
-Uplifting [printf_buffer_number] best 23181 combination 
-Uplifting [printf_format_string] best 23181 combination 
-Uplifting [printf_cls] best 23181 combination 
-Uplifting [main] best 23181 combination 
+Uplifting [memcpy] best 24382 combination zp[2]:12 [ memcpy::src#2 memcpy::src#1 ] zp[2]:14 [ memcpy::dst#2 memcpy::dst#1 ] 
+Uplifting [memset] best 24276 combination zp[2]:10 [ memset::dst#2 memset::dst#4 memset::dst#1 ] zp[2]:48 [ memset::end#0 ] reg byte x [ memset::c#4 ] zp[2]:5 [ memset::num#2 ] zp[2]:7 [ memset::str#3 ] 
+Uplifting [utoa_append] best 23673 combination zp[2]:24 [ utoa_append::value#2 utoa_append::value#0 utoa_append::value#1 ] reg byte x [ utoa_append::digit#2 utoa_append::digit#1 ] zp[2]:59 [ utoa_append::sub#0 ] zp[2]:61 [ utoa_append::return#0 ] zp[2]:57 [ utoa_append::buffer#0 ] 
+Uplifting [printf_ln] best 23673 combination zp[2]:42 [ printf_ln::$0 ] zp[2]:44 [ printf_ln::$1 ] 
+Uplifting [printf_char] best 23637 combination zp[2]:46 [ printf_char::$6 ] reg byte a [ printf_char::ch#3 printf_char::ch#2 printf_char::ch#1 ] 
+Uplifting [printf_str] best 23517 combination zp[2]:2 [ printf_str::str#4 printf_str::str#6 printf_str::str#0 ] reg byte a [ printf_str::ch#0 ] 
+Uplifting [] best 23517 combination zp[2]:35 [ printf_cursor_ptr ] zp[1]:34 [ printf_cursor_y ] zp[1]:33 [ printf_cursor_x ] mem[12] [ printf_buffer ] 
+Uplifting [utoa] best 23383 combination zp[2]:22 [ utoa::buffer#11 utoa::buffer#14 utoa::buffer#4 ] zp[2]:19 [ utoa::value#2 utoa::value#6 utoa::value#1 utoa::value#0 ] zp[1]:18 [ utoa::digit#2 utoa::digit#1 ] reg byte a [ utoa::$10 ] reg byte x [ utoa::started#2 utoa::started#4 ] zp[2]:55 [ utoa::digit_value#0 ] reg byte a [ utoa::$11 ] zp[2]:52 [ utoa::buffer#3 ] 
+Uplifting [atoi] best 23170 combination reg byte y [ atoi::i#4 atoi::i#2 ] zp[2]:31 [ atoi::return#2 atoi::return#0 atoi::res#2 atoi::res#1 ] zp[2]:63 [ atoi::$8 ] zp[2]:65 [ atoi::$9 ] zp[2]:67 [ atoi::$3 ] zp[2]:69 [ atoi::$4 ] reg byte x [ atoi::negative#2 ] zp[2]:27 [ atoi::str#2 ] zp[2]:37 [ atoi::return#3 ] zp[2]:39 [ atoi::return#4 ] 
+Uplifting [printf_number_buffer] best 23161 combination reg byte a [ printf_number_buffer::buffer_sign#0 ] 
+Uplifting [printf_sint] best 23161 combination zp[2]:16 [ printf_sint::value#5 printf_sint::value#0 printf_sint::value#3 printf_sint::value#1 printf_sint::value#2 ] 
+Uplifting [RADIX] best 23161 combination 
+Uplifting [printf_format_number] best 23161 combination 
+Uplifting [printf_buffer_number] best 23161 combination 
+Uplifting [printf_format_string] best 23161 combination 
+Uplifting [printf_cls] best 23161 combination 
+Uplifting [main] best 23161 combination 
 Attempting to uplift remaining variables inzp[1]:34 [ printf_cursor_y ]
-Uplifting [] best 23181 combination zp[1]:34 [ printf_cursor_y ] 
+Uplifting [] best 23161 combination zp[1]:34 [ printf_cursor_y ] 
 Attempting to uplift remaining variables inzp[1]:33 [ printf_cursor_x ]
-Uplifting [] best 23181 combination zp[1]:33 [ printf_cursor_x ] 
+Uplifting [] best 23161 combination zp[1]:33 [ printf_cursor_x ] 
 Attempting to uplift remaining variables inzp[1]:18 [ utoa::digit#2 utoa::digit#1 ]
-Uplifting [utoa] best 23181 combination zp[1]:18 [ utoa::digit#2 utoa::digit#1 ] 
+Uplifting [utoa] best 23161 combination zp[1]:18 [ utoa::digit#2 utoa::digit#1 ] 
 Coalescing zero page register [ zp[2]:35 [ printf_cursor_ptr ] ] with [ zp[2]:46 [ printf_char::$6 ] ] - score: 2
 Coalescing zero page register [ zp[2]:5 [ memset::num#2 ] ] with [ zp[2]:48 [ memset::end#0 ] ] - score: 1
 Coalescing zero page register [ zp[2]:7 [ memset::str#3 ] ] with [ zp[2]:10 [ memset::dst#2 memset::dst#4 memset::dst#1 ] ] - score: 1
@@ -4572,53 +4572,13 @@ Coalescing zero page register [ zp[2]:35 [ printf_cursor_ptr printf_char::$6 pri
 Coalescing zero page register [ zp[2]:55 [ utoa::digit_value#0 ] ] with [ zp[2]:59 [ utoa_append::sub#0 ] ] - score: 1
 Coalescing zero page register [ zp[2]:16 [ printf_sint::value#5 printf_sint::value#0 printf_sint::value#3 printf_sint::value#1 printf_sint::value#2 utoa::value#2 utoa::value#6 utoa::value#1 utoa::value#0 atoi::return#3 atoi::return#4 ] ] with [ zp[2]:24 [ utoa_append::value#2 utoa_append::value#0 utoa_append::value#1 utoa_append::return#0 ] ] - score: 2
 Coalescing zero page register [ zp[2]:16 [ printf_sint::value#5 printf_sint::value#0 printf_sint::value#3 printf_sint::value#1 printf_sint::value#2 utoa::value#2 utoa::value#6 utoa::value#1 utoa::value#0 atoi::return#3 atoi::return#4 utoa_append::value#2 utoa_append::value#0 utoa_append::value#1 utoa_append::return#0 ] ] with [ zp[2]:31 [ atoi::return#2 atoi::return#0 atoi::res#2 atoi::res#1 atoi::$9 atoi::$4 ] ] - score: 2
-Warning! Unknown fragment for statement [131] (signed word~) atoi::$4 ← (signed word~) atoi::$3 + *((to_nomodify byte*) atoi::str#2 + (byte) atoi::i#4)
-Missing ASM fragment Fragment not found vwsz1=vwsz1_plus_pbuz2_derefidx_vbuyy. Attempted variations vwsz1=vwsz1_plus_pbuz2_derefidx_vbuyy 
-File /Users/jespergravgaard/c64/kickc/src/main/kc/lib/stdlib.c
-Line 264
-res * 10 + str[i]
 Coalescing zero page register [ zp[2]:16 [ printf_sint::value#5 printf_sint::value#0 printf_sint::value#3 printf_sint::value#1 printf_sint::value#2 utoa::value#2 utoa::value#6 utoa::value#1 utoa::value#0 atoi::return#3 atoi::return#4 utoa_append::value#2 utoa_append::value#0 utoa_append::value#1 utoa_append::return#0 atoi::return#2 atoi::return#0 atoi::res#2 atoi::res#1 atoi::$9 atoi::$4 ] ] with [ zp[2]:67 [ atoi::$3 ] ] - score: 2
-Warning! Unknown fragment for statement [131] (signed word~) atoi::$4 ← (signed word~) atoi::$3 + *((to_nomodify byte*) atoi::str#2 + (byte) atoi::i#4)
-Missing ASM fragment Fragment not found vwsz1=vwsz1_plus_pbuz2_derefidx_vbuyy. Attempted variations vwsz1=vwsz1_plus_pbuz2_derefidx_vbuyy 
-File /Users/jespergravgaard/c64/kickc/src/main/kc/lib/stdlib.c
-Line 264
-res * 10 + str[i]
 Coalescing zero page register [ zp[2]:12 [ memcpy::src#2 memcpy::src#1 ] ] with [ zp[2]:5 [ memset::num#2 memset::end#0 ] ]
-Warning! Unknown fragment for statement [131] (signed word~) atoi::$4 ← (signed word~) atoi::$3 + *((to_nomodify byte*) atoi::str#2 + (byte) atoi::i#4)
-Missing ASM fragment Fragment not found vwsz1=vwsz1_plus_pbuz2_derefidx_vbuyy. Attempted variations vwsz1=vwsz1_plus_pbuz2_derefidx_vbuyy 
-File /Users/jespergravgaard/c64/kickc/src/main/kc/lib/stdlib.c
-Line 264
-res * 10 + str[i]
 Coalescing zero page register [ zp[2]:14 [ memcpy::dst#2 memcpy::dst#1 ] ] with [ zp[2]:7 [ memset::str#3 memset::dst#2 memset::dst#4 memset::dst#1 ] ]
-Warning! Unknown fragment for statement [131] (signed word~) atoi::$4 ← (signed word~) atoi::$3 + *((to_nomodify byte*) atoi::str#2 + (byte) atoi::i#4)
-Missing ASM fragment Fragment not found vwsz1=vwsz1_plus_pbuz2_derefidx_vbuyy. Attempted variations vwsz1=vwsz1_plus_pbuz2_derefidx_vbuyy 
-File /Users/jespergravgaard/c64/kickc/src/main/kc/lib/stdlib.c
-Line 264
-res * 10 + str[i]
 Coalescing zero page register [ zp[2]:16 [ printf_sint::value#5 printf_sint::value#0 printf_sint::value#3 printf_sint::value#1 printf_sint::value#2 utoa::value#2 utoa::value#6 utoa::value#1 utoa::value#0 atoi::return#3 atoi::return#4 utoa_append::value#2 utoa_append::value#0 utoa_append::value#1 utoa_append::return#0 atoi::return#2 atoi::return#0 atoi::res#2 atoi::res#1 atoi::$9 atoi::$4 atoi::$3 ] ] with [ zp[2]:2 [ printf_str::str#4 printf_str::str#6 printf_str::str#0 ] ]
-Warning! Unknown fragment for statement [131] (signed word~) atoi::$4 ← (signed word~) atoi::$3 + *((to_nomodify byte*) atoi::str#2 + (byte) atoi::i#4)
-Missing ASM fragment Fragment not found vwsz1=vwsz1_plus_pbuz2_derefidx_vbuyy. Attempted variations vwsz1=vwsz1_plus_pbuz2_derefidx_vbuyy 
-File /Users/jespergravgaard/c64/kickc/src/main/kc/lib/stdlib.c
-Line 264
-res * 10 + str[i]
 Coalescing zero page register [ zp[2]:27 [ atoi::str#2 ] ] with [ zp[2]:22 [ utoa::buffer#11 utoa::buffer#14 utoa::buffer#4 utoa::buffer#3 utoa_append::buffer#0 ] ]
-Warning! Unknown fragment for statement [131] (signed word~) atoi::$4 ← (signed word~) atoi::$3 + *((to_nomodify byte*) atoi::str#2 + (byte) atoi::i#4)
-Missing ASM fragment Fragment not found vwsz1=vwsz1_plus_pbuz2_derefidx_vbuyy. Attempted variations vwsz1=vwsz1_plus_pbuz2_derefidx_vbuyy 
-File /Users/jespergravgaard/c64/kickc/src/main/kc/lib/stdlib.c
-Line 264
-res * 10 + str[i]
 Coalescing zero page register [ zp[2]:63 [ atoi::$8 ] ] with [ zp[2]:55 [ utoa::digit_value#0 utoa_append::sub#0 ] ]
-Warning! Unknown fragment for statement [131] (signed word~) atoi::$4 ← (signed word~) atoi::$3 + *((to_nomodify byte*) atoi::str#2 + (byte) atoi::i#4)
-Missing ASM fragment Fragment not found vwsz1=vwsz1_plus_pbuz2_derefidx_vbuyy. Attempted variations vwsz1=vwsz1_plus_pbuz2_derefidx_vbuyy 
-File /Users/jespergravgaard/c64/kickc/src/main/kc/lib/stdlib.c
-Line 264
-res * 10 + str[i]
 Coalescing zero page register [ zp[2]:27 [ atoi::str#2 utoa::buffer#11 utoa::buffer#14 utoa::buffer#4 utoa::buffer#3 utoa_append::buffer#0 ] ] with [ zp[2]:12 [ memcpy::src#2 memcpy::src#1 memset::num#2 memset::end#0 ] ]
-Warning! Unknown fragment for statement [131] (signed word~) atoi::$4 ← (signed word~) atoi::$3 + *((to_nomodify byte*) atoi::str#2 + (byte) atoi::i#4)
-Missing ASM fragment Fragment not found vwsz1=vwsz1_plus_pbuz2_derefidx_vbuyy. Attempted variations vwsz1=vwsz1_plus_pbuz2_derefidx_vbuyy 
-File /Users/jespergravgaard/c64/kickc/src/main/kc/lib/stdlib.c
-Line 264
-res * 10 + str[i]
 Coalescing zero page register [ zp[2]:63 [ atoi::$8 utoa::digit_value#0 utoa_append::sub#0 ] ] with [ zp[2]:14 [ memcpy::dst#2 memcpy::dst#1 memset::str#3 memset::dst#2 memset::dst#4 memset::dst#1 ] ]
 Allocated (was zp[2]:16) zp[2]:2 [ printf_sint::value#5 printf_sint::value#0 printf_sint::value#3 printf_sint::value#1 printf_sint::value#2 utoa::value#2 utoa::value#6 utoa::value#1 utoa::value#0 atoi::return#3 atoi::return#4 utoa_append::value#2 utoa_append::value#0 utoa_append::value#1 utoa_append::return#0 atoi::return#2 atoi::return#0 atoi::res#2 atoi::res#1 atoi::$9 atoi::$4 atoi::$3 printf_str::str#4 printf_str::str#6 printf_str::str#0 ]
 Allocated (was zp[1]:18) zp[1]:4 [ utoa::digit#2 utoa::digit#1 ]
@@ -4627,11 +4587,6 @@ Allocated (was zp[1]:33) zp[1]:7 [ printf_cursor_x ]
 Allocated (was zp[1]:34) zp[1]:8 [ printf_cursor_y ]
 Allocated (was zp[2]:35) zp[2]:9 [ printf_cursor_ptr printf_char::$6 printf_ln::$0 printf_ln::$1 ]
 Allocated (was zp[2]:63) zp[2]:11 [ atoi::$8 utoa::digit_value#0 utoa_append::sub#0 memcpy::dst#2 memcpy::dst#1 memset::str#3 memset::dst#2 memset::dst#4 memset::dst#1 ]
-Warning! Unknown fragment for statement [131] (signed word~) atoi::$4 ← (signed word~) atoi::$3 + *((to_nomodify byte*) atoi::str#2 + (byte) atoi::i#4)
-Missing ASM fragment Fragment not found vwsz1=vwsz1_plus_pbuz2_derefidx_vbuyy. Attempted variations vwsz1=vwsz1_plus_pbuz2_derefidx_vbuyy 
-File /Users/jespergravgaard/c64/kickc/src/main/kc/lib/stdlib.c
-Line 264
-res * 10 + str[i]
 
 ASSEMBLER BEFORE OPTIMIZATION
   // File Comments
@@ -5448,8 +5403,14 @@ atoi: {
     // [130] (signed word~) atoi::$3 ← (signed word~) atoi::$9 << (byte) 1 -- vwsz1=vwsz1_rol_1 
     asl.z __3
     rol.z __3+1
-    // [131] (signed word~) atoi::$4 ← (signed word~) atoi::$3 + *((to_nomodify byte*) atoi::str#2 + (byte) atoi::i#4)
-    .assert "Missing ASM fragment Fragment not found vwsz1=vwsz1_plus_pbuz2_derefidx_vbuyy. Attempted variations vwsz1=vwsz1_plus_pbuz2_derefidx_vbuyy ", 0, 1
+    // [131] (signed word~) atoi::$4 ← (signed word~) atoi::$3 + *((to_nomodify byte*) atoi::str#2 + (byte) atoi::i#4) -- vwsz1=vwsz1_plus_pbuz2_derefidx_vbuyy 
+    clc
+    lda.z __4
+    adc (str),y
+    sta.z __4
+    bcc !+
+    inc.z __4+1
+  !:
     // [132] (signed word) atoi::res#1 ← (signed word~) atoi::$4 - (byte) '0' -- vwsz1=vwsz1_minus_vbuc1 
     sec
     lda.z res
@@ -5925,7 +5886,7 @@ mem[12] [ printf_buffer ]
 
 
 FINAL ASSEMBLER
-Score: 19613
+Score: 19823
 
   // File Comments
 // Test atoi()
@@ -6693,8 +6654,14 @@ atoi: {
     asl.z __3
     rol.z __3+1
     // res * 10 + str[i]
-    // [131] (signed word~) atoi::$4 ← (signed word~) atoi::$3 + *((to_nomodify byte*) atoi::str#2 + (byte) atoi::i#4)
-    .assert "Missing ASM fragment Fragment not found vwsz1=vwsz1_plus_pbuz2_derefidx_vbuyy. Attempted variations vwsz1=vwsz1_plus_pbuz2_derefidx_vbuyy ", 0, 1
+    // [131] (signed word~) atoi::$4 ← (signed word~) atoi::$3 + *((to_nomodify byte*) atoi::str#2 + (byte) atoi::i#4) -- vwsz1=vwsz1_plus_pbuz2_derefidx_vbuyy 
+    clc
+    lda.z __4
+    adc (str),y
+    sta.z __4
+    bcc !+
+    inc.z __4+1
+  !:
     // res = res * 10 + str[i] - '0'
     // [132] (signed word) atoi::res#1 ← (signed word~) atoi::$4 - (byte) '0' -- vwsz1=vwsz1_minus_vbuc1 
     sec