4 files changed, 128 insertions, 5 deletions

diff --git a/programs/echo.pal b/programs/echo.pal
index 4e59623..83b46e8 100644
--- a/programs/echo.pal
+++ b/programs/echo.pal
@@ -1,13 +1,11 @@
 / vim: set sw=8 noexpandtab :
 
 *200
+        TFL
 LOOP,   TSF
-        JMS ECHO
         JMP LOOP
-
-ECHO,   0
 WAIT,   KSF
         JMP WAIT
         KRB
         TLS
-        JMP I ECHO
+        JMP LOOP
diff --git a/programs/echo_int.pal b/programs/echo_int.pal
new file mode 100644
index 0000000..62886ff
--- /dev/null
+++ b/programs/echo_int.pal
@@ -0,0 +1,58 @@
+/ vim: set sw=8 noexpandtab :
+
+*000
+
+INTRET, 0
+        JMP GOTINT
+
+*010
+
+HEAD,   7777            / because preincrement
+TAIL,   7777
+
+*200
+
+        CLA IAC
+        KIE
+        ION
+        CLA
+LOOP,   TAD TAIL
+        CMA IAC
+        TAD HEAD
+        SNA
+        JMP LOOP
+        CLA
+        CDF 0010
+        TAD I TAIL
+        CDF 0000
+        IOF             / critical section
+        TLS
+BUSY,   TSF             / FIXME: remove busy wait inside IOF (see echo_optimal.pal)
+        JMP BUSY
+        TCF
+        ION
+        CLA             / end critical section
+        JMP LOOP
+
+*400
+
+SAVEA,  0
+SAVEF,  0
+
+GOTINT, DCA SAVEA
+        GTF
+        AND (7577)
+        DCA SAVEF
+        KSF
+        JMP RETINT
+        KRB
+        CDF 0010
+        DCA I HEAD
+        CDF 0000
+RETINT, CLA
+        TAD SAVEF
+        RTF
+        CLA
+        TAD SAVEA
+        ION
+        JMP I INTRET
diff --git a/programs/echo_optimal.pal b/programs/echo_optimal.pal
new file mode 100644
index 0000000..1281309
--- /dev/null
+++ b/programs/echo_optimal.pal
@@ -0,0 +1,67 @@
+/ vim: set sw=8 noexpandtab :
+
+*000
+
+INTRET, 0
+        JMP GOTINT
+
+*010
+
+HEAD,   7777            / because preincrement
+TAIL,   7777
+
+*100
+
+TTBUSY, 0               / FIXME: sometimes we get wedged with TTBUSY=1, but TT flag is clear (no TT interrupt occurs)
+
+*200
+
+        CLA IAC
+        KIE
+        ION
+        CLA
+LOOP,   TAD TTBUSY
+        SZA
+        JMP LOOP
+        TAD TAIL
+        CMA IAC
+        TAD HEAD
+        SNA
+        JMP LOOP
+        CLA
+        CDF 0010
+        TAD I TAIL
+        CDF 0000
+        IOF             / critical section
+        TPC
+        CLA IAC
+        ION
+        DCA TTBUSY      / end critical section
+        JMP LOOP
+
+*400
+
+SAVEA,  0
+SAVEF,  0
+
+GOTINT, DCA SAVEA
+        GTF
+        AND (7577)
+        DCA SAVEF
+        TSF
+        JMP KBIN
+        DCA TTBUSY
+        TCF
+KBIN,   KSF
+        JMP RETINT
+        KRB
+        CDF 0010
+        DCA I HEAD
+        CDF 0000
+RETINT, CLA
+        TAD SAVEF
+        RTF
+        CLA
+        TAD SAVEA
+        ION
+        JMP I INTRET
diff --git a/programs/mike_fib.pal b/programs/fib_mike.pal
index 6f56109..a20a843 100644
--- a/programs/mike_fib.pal
+++ b/programs/fib_mike.pal
@@ -9,7 +9,7 @@ LOOP,	CLA
         TAD FIB0
         JMS PUTN
         CLA
-        TAD (054)
+        TAD (012)
         JMS PUTC
         CLA
         TAD FIB0