Add punched tape functionality

gidubba.asm

@@ -247,6 +247,16 @@ cnarg:  load    r1, ucp
         breq    r0, r1, print
         load    r1, lcp
         breq    r0, r1, print
+        ;Write to tape
+        load    r1, ucw
+        breq    r0, r1, write
+        load    r1, lcw
+        breq    r0, r1, write
+        ;Read from tape
+        load    r1, ucr
+        breq    r0, r1, read
+        load    r1, lcr
+        breq    r0, r1, read
         ;Halt
         load    r1, uch
         breq    r0, r1, end
@@ -609,39 +619,77 @@ lstend: load    r0, count
 
         ;Print the text
 
+        ;Get the printer address
+        ;High byte
+print:  load    r0, cstff
+        store   prwrch + 1, r0
+        ;Low byte
+        load    r0, cstfe
+        store   prwrch + 2, r0
+
+        ;Print
+        cleq    r0, r0, prwr
+
+        ;Return to the command prompt
+        breq    r0, r0, cmdp
+
+        ;***
+
+        ;Write the text to tape
+
+        ;Get the keypunch address
+        ;High byte
+write:  load    r0, cstff
+        store   prwrch + 1, r0
+        ;Low byte
+        load    r0, cstfd
+        store   prwrch + 2, r0
+
+        ;Write
+        cleq    r0, r0, prwr
+
+        ;Write a substitute
+        load    r0, sub
+        store   fffd, r0
+
+        ;Return to the command prompt
+        breq    r0, r0, cmdp
+
+        ;***
+
+        ;Read the text from tape
+
         ;Get the save start address
         ;High byte
-print:  load    r0, svstrt
+read:   load    r0, svstrt
-        store   chprnt + 1, r0
+        store   chrsto + 1, r0
         ;Low byte
         load    r0, svstrt + 1
-        store   chprnt + 2, r0
+        store   chrsto + 2, r0
 
-        ;Load a character from the save
+        ;Read and store a character
-chprnt: load    r1, buffer + 100
+chread: load    r1, fffd
+chrsto: store   buffer + 100, r1
 
         ;Check for the save end
         load    r2, sub
-        breq    r1, r2, prend
+        breq    r1, r2, redend
-
-        ;Print the character
-        store   fffe, r1
 
         ;Increment the save address
         ;Load the address
-        load    r0, chprnt + 1
+        load    r0, chrsto + 1
-        load    r1, chprnt + 2
+        load    r1, chrsto + 2
         ;Increment
         cleq    r0, r0, incdw
         ;Store the address
-        store   chprnt + 1, r0
+        store   chrsto + 1, r0
-        store   chprnt + 2, r1
+        store   chrsto + 2, r1
 
-        ;Print the next character
+        ;Read the next character
-        breq    r0, r0, chprnt
+        breq    r0, r0, chread
 
         ;Return to the command prompt
-prend:  breq    r0, r0, cmdp
+redend: breq    r0, r0, cmdp
 
         ;***
 
@@ -1238,6 +1286,44 @@ prcln:  load    r0, colon
 
         ;***
 
+        ;Print or write to tape
+
+        ;Get the save start address
+        ;High byte
+prwr:   load    r0, svstrt
+        store   chprwr + 1, r0
+        ;Low byte
+        load    r0, svstrt + 1
+        store   chprwr + 2, r0
+
+        ;Load a character from the save
+chprwr: load    r1, buffer + 100
+
+        ;Check for the save end
+        load    r2, sub
+        breq    r1, r2, pwend
+
+        ;Print the character
+prwrch: store   fffe, r1
+
+        ;Increment the save address
+        ;Load the address
+        load    r0, chprwr + 1
+        load    r1, chprwr + 2
+        ;Increment
+        cleq    r0, r0, incdw
+        ;Store the address
+        store   chprwr + 1, r0
+        store   chprwr + 2, r1
+
+        ;Print the next character
+        breq    r0, r0, chprwr
+
+        ;Return
+pwend:  ret
+
+        ;***
+
         ;Data
 
         ;Constants
@@ -1258,6 +1344,8 @@ constd: data     d
 conste: data     e
 constf: data     f
 constf: data     f
+cstfd:  data    fd
+cstfe:  data    fe
 cstff:  data    ff
 
         ;Characters
@@ -1292,6 +1380,8 @@ uch:    data    48
 uci:    data    49
 ucl:    data    4c
 ucp:    data    50
+ucr:    data    52
+ucw:    data    57
 bslash: data    5c
 lca:    data    61
 lcb:    data    62
@@ -1303,6 +1393,8 @@ lch:    data    68
 lci:    data    69
 lcl:    data    6c
 lcp:    data    70
+lcr:    data    72
+lcw:    data    77
 
         ;Variables
 ovrflw: data     0
@@ -1326,10 +1418,6 @@ count:  data     0
 cmpadr: data     0
         data     0
 
-
-
-
-
         ;Buffer and save
 bfstrt: addr    buffer
 bfsize: data    fe

readme.md

@@ -10,9 +10,9 @@ System requirements
 -------------------
 
 Gidubba requires a terminal with local echo at address FFFF and
-optionally a line printer at address FFFE. The emulator implementation
+optionally a line printer at address FFFE and a punched tape reader and
-included in the Thingamajig repository is suitable. If your setup
+keypunch at FFFD. If your setup differs from this you may have to modify
-differs from this you may have to modify the code yourself.
+the code yourself.
 
 Usage
 -----
@@ -33,6 +33,8 @@ Commands with two arguments:
 
 Commands with no argument:
   * P: Print (requires a printer)
+  * W: Writes to tape (requires a keypunch)
+  * R: Reads from tape (requires a tape reader)
   * H: Halt
 
 Both commands and arguments are case-insensitive. In both the command