Add printer echo support

doc/DRAWL.md

@@ -21,6 +21,132 @@ However, the code is partitioned to allow for easy extension so some of these mi
 - Bit-wise logic operations on 32 bit integers
 - Hexadecimal input/output
 
+Thes DRAWL implementation comes with the follwoing built-in:
+
+### Constants
+- T = True
+- F = False
+- NIL = NULL
+- SPACE = SPACE character on output
+- CR = Carriage Return character on output
+- CSET()
+- CSETQ()
+- DEFINE()
+
+### Function types
+
+- LAMBDA
+- FUNARG
+- FUNCTION
+
+
+### Predicates
+
+- ATOM()
+- EQ()
+- NOT()
+- AND(...)
+- OR(...)
+- NULL()
+
+### Misc
+
+- SET
+- QUOTE()
+- ARRAY
+- TRACE() = Turn tracing on/off
+- GC() = Run garbage collector and return free memory amount
+- QUIT() = Exit REPL
+
+### List manipulation
+
+- CAR()
+- CDR()
+- CONS()
+- LIST(...)
+
+### Conditionals
+
+- COND(...)
+- IF()
+
+### Output
+
+- PRHEX() = Turn hexadecimal output on/off
+- PRI(...) = Print without newline
+- PRINT(...) = Print with newline
+- FMTFPI() = Floating point format integer digits
+- FMTFPF() = Floating point format fractional digits
+- PRINTER() = Turn printer echo on/off on slot#
+
+### Looping
+
+- FOR()
+- WHILE()
+- UNTIL()
+
+### Associations
+
+- LABEL()
+- SET()
+- SETQ()
+
+### Program feature
+
+- PROG
+- GO()
+- RETURN()
+
+### Numbers
+
+- +()
+- -()
+- '\*'()
+- /()
+- REM()
+- NEG()
+- ABS()
+- >()
+- <()
+- MIN()
+- MAX()
+
+### Integers
+
+- BITNOT() = Bit-wise NOT
+- BITAND() = Bit-wise AND
+- BITOR() = Bit-wise OR
+- BITXOR= Bit-wise XOR
+- SHIFT() = Bit-wise SHIFT (positive = left, negative = right)
+- ROTATE() = Bit-wise ROTATE (positive = left, negative = right)
+
+### Floating Point (from the SANE library)
+
+- PI()
+- MATH_E()
+- LOGB()
+- SCALEB_I()
+- TRUNCATE()
+- ROUND()
+- SQRT()
+- COS()
+- SIN()
+- TAN()
+- ATAN()
+- LOG2()
+- LOG2_1()
+- LN()
+- LN_1()
+- POW2()
+- POW2_1()
+- POWE()
+- POWE_1()
+- POWE2_1()
+- POW_I()
+- POWY()
+- COMP()
+- ANNUITY()
+
 LISP is one of the earliest computer languages. As such, it holds a special place in the anals of computer science. I've always wanted to learn why LISP is held in such high regard by so many, so I went about learning LISP by actually implementing a LISP interpreter in PLASMA. PLASMA is well suited to implement other languages due to its rich syntax, performance and libraries.
 
 ## Links
@@ -29,6 +155,10 @@ Here are some links to get you started.
 
 LISP 1.5 Manual: https://archive.org/details/bitsavers_mitrlelisprammersManual2ed1985_9279667
 
+LISP 1.5 Primer: https://www.softwarepreservation.org/projects/LISP/book/Weismann_LISP1.5_Primer_1967.pdf
+
+Apple Numerics Manual (SANE): https://vintageapple.org/inside_o/pdf/Apple_Numerics_Manual_Second_Edition_1988.pdf
+
 Video showing DRAWL in action: https://youtu.be/wBMivg6xfSg
 
 Preconfigured PLASMA ProDOS boot floppy for DRAWL: https://github.com/dschmenk/PLASMA/blob/master/images/apple/DRAWL.po

src/lisp/drawl.pla

@@ -59,10 +59,14 @@ import smath
   predef eval_int(expr)#1
 end
 
+
 var prog, prog_expr, prog_return // Current PROG expressions
 var sym_cond, sym_if, sym_fpint, sym_fpfrac
 var pred_true
 
+const csw   = $0036              // Output switch vector
+var scrncsw = 0                  // Output screen value
+
 const FILEBUF_SIZE = 128
 var readfn                       // Read input routine
 var fileref, filebuf             // File read vars
@@ -174,6 +178,24 @@ def natv_gc(symptr, expr)
   return new_int(heapavail, 0)
 end
 
+def natv_printer(symptr, expr)
+  byte slot
+
+  slot = eval_int(expr)=>intval & 7
+  if slot
+    if !scrncsw
+      scrncsw = *csw
+    fin
+    *csw = $C000 | (slot << 8)
+  else
+    if scrncsw
+      *csw = scrncsw
+    fin
+    scrncsw = 0
+  fin
+  return new_int(slot, 0)
+end
+
 def natv_bye(symptr, expr)
   quit = TRUE
   return new_sym("GOODBYE!")
@@ -267,22 +289,23 @@ end
 //
 
 puts("DRAWL (LISP 1.5) symbolic processor\n")
-pred_true               = bool_pred(TRUE) // Capture value of TRUE
+pred_true                = bool_pred(TRUE) // Capture value of TRUE
-sym_fpint               = new_sym("FMTFPI")
+sym_fpint                = new_sym("FMTFPI")
-sym_fpfrac              = new_sym("FMTFPF")
+sym_fpfrac               = new_sym("FMTFPF")
-sym_fpint=>natv         = @natv_fpint
+sym_fpint=>natv          = @natv_fpint
-sym_fpfrac=>natv        = @natv_fpfrac
+sym_fpfrac=>natv         = @natv_fpfrac
-sym_fpint=>apval        = new_int(fmt_fpint,  0) ^ NULL_HACK
+sym_fpint=>apval         = new_int(fmt_fpint,  0) ^ NULL_HACK
-sym_fpfrac=>apval       = new_int(fmt_fpfrac, 0) ^ NULL_HACK
+sym_fpfrac=>apval        = new_int(fmt_fpfrac, 0) ^ NULL_HACK
-sym_cond                = new_sym("COND") // This should actually match COND
+sym_cond                 = new_sym("COND") // This should actually match COND
-sym_if                  = new_sym("IF")   // This should actually match IF
+sym_if                   = new_sym("IF")   // This should actually match IF
-new_sym("PROG")=>natv   = @natv_prog
+new_sym("PROG")=>natv    = @natv_prog
-new_sym("GO")=>natv     = @natv_go
+new_sym("GO")=>natv      = @natv_go
-new_sym("RETURN")=>natv = @natv_return
+new_sym("RETURN")=>natv  = @natv_return
-new_sym("SET")=>natv    = @natv_set
+new_sym("SET")=>natv     = @natv_set
-new_sym("SETQ")=>natv   = @natv_setq
+new_sym("SETQ")=>natv    = @natv_setq
-new_sym("GC")=>natv     = @natv_gc
+new_sym("GC")=>natv      = @natv_gc
-new_sym("QUIT")=>natv   = @natv_bye
+new_sym("PRINTER")=>natv = @natv_printer
+new_sym("QUIT")=>natv    = @natv_bye
 
 parse_cmdline
 while not quit