mdw@git.distorted.org.uk Git - ssr/blob - StraySrc/Libraries/Sapphire/sail/_s/getToken

   1 ;
   2 ; getToken.s
   3 ;
   4 ; The getting of the next token from the input file
   5 ;
   6 ; © 1995 Straylight
   7 ;
   8
   9 ;----- Standard Header ------------------------------------------------------
  10
  11                 GET     libs:header
  12                 GET     libs:swis
  13
  14                 GET     libs:stream
  15
  16 ;----- External dependencies ------------------------------------------------
  17
  18                 GET     sh.anchor
  19
  20 ;----- Main code ------------------------------------------------------------
  21
  22                 AREA    |TermScript$$Code|,CODE,READONLY
  23
  24 ; --- getToken ---
  25 ;
  26 ; On entry:     R9 == previous token, or -1
  27 ;               R10 == pointer into the tokenised buffer
  28 ;               R12 == anchor block pointer
  29 ;
  30 ; On exit:      R7 == token class of token read
  31 ;               R8 == index of token in token class
  32 ;               R9 == new lookahead token
  33 ;               R10 == moved on to the first character after the rvalue
  34 ;
  35 ; Use:          Tries to read an token from the current input line
  36
  37                 EXPORT  getToken
  38 getToken        ROUT
  39
  40 10getToken      CMP     R9,#10                  ;Is it a newline?
  41                 BEQ     %20getToken             ;A newline -- bump line count
  42                 LDRB    R9,[R10],#1             ;Load a byte
  43                 CMP     R9,#31                  ;Is it an implicit newline?
  44                 BEQ     %20getToken             ;Yes -- bump line counter
  45
  46 15getToken      ADR     R8,tokClasses           ;Point to class table
  47                 LDR     R8,[R8,R9,LSL #1]
  48                 AND     R7,R8,#&FF
  49                 AND     R8,R8,#&FF00
  50                 MOV     R8,R8,LSR #8
  51                 MOVS    PC,R14                  ;Return to caller
  52
  53 20getToken      LDR     R7,tsc_line             ;Yes -- get current line
  54                 ADD     R7,R7,#1                ;Increment line num
  55                 STR     R7,tsc_line             ;And save new line number
  56                 LDRB    R9,[R10],#1             ;Load a byte
  57                 CMP     R9,#31                  ;Should we ignore this char?
  58                 BEQ     %20getToken             ;Yes -- look for the next
  59                 B       %15getToken
  60
  61                 GET     sh.tokClasses
  62
  63                 LTORG
  64
  65 ;----- That's all, folks ----------------------------------------------------
  66
  67                 END