diff --git a/int64.asm b/int64.asm
new file mode 100644
index 0000000..b166a66
--- /dev/null
+++ b/int64.asm
@@ -0,0 +1,92 @@
+         keep  obj/int64
+         mcopy int64.macros
+         case  on
+
+****************************************************************
+*
+*  Int64 - 64-bit integer math routines.
+*
+*  This code implements routines called by ORCA/C generated
+*  code for operations on 64-bit integers.
+*
+****************************************************************
+*
+Int64    start                          dummy segment
+         end
+
+****************************************************************
+*
+*  ~UMUL8 - Eight Byte Unsigned Integer Multiply
+*
+*  Inputs:
+*        NUM1,NUM2 - operands
+*
+*  Outputs:
+*        NUM2 - result
+*
+****************************************************************
+*
+~UMUL8   START
+
+ANS      EQU   3
+RETURN   EQU   ANS+16
+NUM1     EQU   RETURN+3
+NUM2     EQU   NUM1+8
+
+         LDA   #0                       set up initial working value
+         PHA
+         PHA
+         PHA
+         PHA
+         LDA   18,s                     initially, ANS = NUM1
+         PHA
+         LDA   18,s
+         PHA
+         LDA   18,s
+         PHA
+         LDA   18,s
+         PHA
+         PHD
+         TSC
+         TCD        
+;
+;  Do a 64 bit by 64 bit multiply.
+;
+         LDY   #64                      64 bit multiply
+ML1      LDA   ANS
+         LSR   A
+         BCC   ML2
+         CLC                            add multiplicand to the partial product
+         LDA   ANS+8
+         ADC   NUM2
+         STA   ANS+8
+         LDA   ANS+10
+         ADC   NUM2+2
+         STA   ANS+10
+         LDA   ANS+12
+         ADC   NUM2+4
+         STA   ANS+12
+         LDA   ANS+14
+         ADC   NUM2+6
+         STA   ANS+14
+ML2      ROR   ANS+14                   shift the interim result
+         ROR   ANS+12
+         ROR   ANS+10
+         ROR   ANS+8
+         ROR   ANS+6
+         ROR   ANS+4
+         ROR   ANS+2
+         ROR   ANS
+         DEY                            loop until done
+         BNE   ML1
+
+         move4 ANS,NUM2                 move return value and address
+         move4 ANS+4,NUM2+4
+         move4 RETURN-1,NUM1+4
+         PLD                            fix stack, DP
+         TSC
+         CLC
+         ADC   #24
+         TCS
+         RTL
+         END
diff --git a/int64.macros b/int64.macros
new file mode 100644
index 0000000..aedead3
--- /dev/null
+++ b/int64.macros
@@ -0,0 +1,123 @@
+ macro
+&l move4 &m1,&m2
+ lclb &yistwo
+&l ~setm
+ ~lda &m1
+ ~sta &m2
+ ~lda.h &m1
+ ~sta.h &m2
+ ~restm
+ mend
+ macro
+&l ~lda &op
+ lclc &c
+&c amid "&op",1,1
+ aif "&c"<>"{",.b
+&c amid "&op",l:&op,1
+ aif "&c"="}",.a
+ mnote "Missing closing '}'",2
+&op setc &op}
+.a
+&op amid "&op",2,l:&op-2
+&op setc (&op)
+.b
+&l lda &op
+ mend
+ macro
+&l ~lda.h &op
+&l anop
+ lclc &c
+&c amid "&op",1,1
+ aif "&c"="[",.b
+ aif "&c"<>"{",.d
+&c amid "&op",l:&op,1
+ aif "&c"="}",.a
+ mnote "Missing closing '}'",2
+&op setc &op}
+.a
+&op amid "&op",2,l:&op-2
+&op setc (&op)
+.b
+ aif &yistwo,.c
+&yistwo setb 1
+ ldy #2
+.c
+&op setc "&op,y"
+ lda &op
+ mexit
+.d
+ aif "&c"<>"#",.e
+&op amid "&op",2,l:&op-1
+&op setc "#^&op"
+ lda &op
+ mexit
+.e
+ lda 2+&op
+ mend
+ macro
+&l ~restm
+&l anop
+ aif (&~la+&~li)=2,.i
+ sep #32*(.not.&~la)+16*(.not.&~li)
+ aif &~la,.h
+ longa off
+.h
+ aif &~li,.i
+ longi off
+.i
+ mend
+ macro
+&l ~setm
+&l anop
+ aif c:&~la,.b
+ gblb &~la
+ gblb &~li
+.b
+&~la setb s:longa
+&~li setb s:longi
+ aif s:longa.and.s:longi,.a
+ rep #32*(.not.&~la)+16*(.not.&~li)
+ longa on
+ longi on
+.a
+ mend
+ macro
+&l ~sta &op
+ lclc &c
+&c amid "&op",1,1
+ aif "&c"<>"{",.b
+&c amid "&op",l:&op,1
+ aif "&c"="}",.a
+ mnote "Missing closing '}'",2
+&op setc &op}
+.a
+&op amid "&op",2,l:&op-2
+&op setc (&op)
+.b
+&l sta &op
+ mend
+ macro
+&l ~sta.h &op
+&l anop
+ lclc &c
+&c amid "&op",1,1
+ aif "&c"="[",.b
+ aif "&c"<>"{",.d
+&c amid "&op",l:&op,1
+ aif "&c"="}",.a
+ mnote "Missing closing '}'",2
+&op setc &op}
+.a
+&op amid "&op",2,l:&op-2
+&op setc (&op)
+.b
+ aif &yistwo,.c
+&yistwo setb 1
+ ldy #2
+.c
+&op setc "&op,y"
+ sta &op
+ mexit
+.d
+ sta 2+&op
+ mend
diff --git a/make b/make
index a436612..1676424 100644
--- a/make
+++ b/make
@@ -19,7 +19,7 @@ if {#} == 0
       unset exit
    end
 
-   for i in cc ctype string stdlib time setjmp orca fcntl vars toolglue signal
+   for i in cc ctype string stdlib time setjmp orca fcntl vars toolglue signal int64
       Newer obj/{i}.a {i}.asm
       if {Status} != 0
          set exit on
@@ -39,7 +39,7 @@ echo delete orcalib
 delete orcalib
 
 set list        vars.a assert.a cc.a setjmp.a ctype.a string.a stdlib.a
-set list {list} time.a signal.a toolglue.a orca.a fcntl.a stdio.a
+set list {list} time.a signal.a toolglue.a orca.a fcntl.a stdio.a int64.a
 for i in {list}
    echo makelib orcalib +obj/{i}
    makelib orcalib +obj/{i}