documented recent changes

diff --git a/doc/ncg.doc b/doc/ncg.doc
index e5464b4..37ad969 100644 (file)
--- a/doc/ncg.doc
+++ b/doc/ncg.doc
@@ -301,16 +301,16 @@ Here is a list of reserved words; all of these are unavailable as identifiers.
 .TS
 box;
 l l l l l.
-ADDR   STACK   from    reg_any test
-COERCIONS      STACKINGRULES   gen     reg_float       to
-INSTRUCTIONS   TESTS   highw   reg_loop        ufit
-INT    TIMEFACTOR      inreg   reg_pointer     uses
-MOVES  TOKENS  kills   regvar  with
-PATTERNS       call    leaving return  yields
-PROPERTIES     cost    loww    reusing 
-REGISTERS      defined move    rom     
-SETS   exact   pat     samesign        
-SIZEFACTOR     example proc    sfit    
+ADDR   STACK   from    proc    sfit
+COERCIONS      STACKINGRULES   gen     reg_any test
+INSTRUCTIONS   TESTS   highw   reg_float       to
+INT    TIMEFACTOR      inreg   reg_loop        ufit
+MOVES  TOKENS  is_rom  reg_pointer     uses
+PATTERNS       call    kills   regvar  with
+PROPERTIES     cost    leaving return  yields
+REGISTERS      defined loww    reusing
+SETS   exact   move    rom
+SIZEFACTOR     example pat     samesign
 .TE
 C style comments are accepted.
 .DS
@@ -883,6 +883,14 @@ number
 .I a
 in the EM-pattern.
 Undefined if that descriptor does not exist.
+.IP is_rom($a)
+Integer expression indicating whether EM instruction number
+.I a
+in the EM-pattern refers to ROM. This may be useful for generating 
+position-independent code with the ROM in read-only memory.
+.I Is_rom
+enables one to see the difference between ROM references and other data
+references.
 .IP loww($a)
 Returns the lower half of the argument of EM instruction number
 .I a .
@@ -1656,10 +1664,10 @@ The current version of
 .I cgg
 does not check correctness of the example, so be careful.
 .PP
-A procedure is called with one or two string-parameters,
+A procedure is called with string-parameters,
 that are assembler opcodes.
-They can be accessed by appending the strings `[1]' or `[2]'
-to a table opcode.
+They can be accessed by appending the string `[<number>]'
+to a table opcode, where <number> is the parameter number.
 The string `*' can be used as an equivalent for `[1]'.
 Just in case this is not clear, here is an example for
 a procedure to increment/decrement a register.
@@ -1676,7 +1684,7 @@ The procedure is called with parameter "inc" or "dec".
 The procedure call is given instead of the code-part of the
 code rule and looks like this
 .DS
-call <identifier> '(' string [ ',' string ] ')'
+call <identifier> '(' <comma-separated list of strings> ')'
 .DE
 which leads to the following large example:
 .DS