From fa080de7afc95aa1c19a6e6fc0e0708ced2eadc4 Mon Sep 17 00:00:00 2001 From: Joseph Hunkeler Date: Wed, 8 Jul 2015 20:46:52 -0400 Subject: Initial commit --- sys/gio/cursor/gtrfetch.x | 48 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 48 insertions(+) create mode 100644 sys/gio/cursor/gtrfetch.x (limited to 'sys/gio/cursor/gtrfetch.x') diff --git a/sys/gio/cursor/gtrfetch.x b/sys/gio/cursor/gtrfetch.x new file mode 100644 index 00000000..44ccfe60 --- /dev/null +++ b/sys/gio/cursor/gtrfetch.x @@ -0,0 +1,48 @@ +# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc. + +include +include +include "gtr.h" + +# GTR_FETCH_NEXT_INSTRUCTION -- Return a pointer to the next GKI metacode +# instruction in the input buffer. Only complete instructions resident in +# a contiguous section of memory are returned. EOF is returned when the +# end of the current buffer is reached, or when the last instruction in the +# frame buffer is not yet complete. EOF does not signify the end of the +# metacode stream. + +int procedure gtr_fetch_next_instruction (tr, gki) + +pointer tr # pointer to giotr descriptor +pointer gki # pointer to next instruction (output) + +int nleft, length +pointer ip, itop + +begin + ip = TR_IP(tr) + itop = TR_OP(tr) + + # Search for the beginning of the next instruction. + while (Mems[ip] != BOI && ip < itop) + ip = ip + 1 + + nleft = itop - ip + if (nleft < 3) { + # The length field of the next instruction is not yet present. + TR_IP(tr) = ip + return (EOF) + } else { + length = Mems[ip+GKI_HDR_LENGTH-1] + if (length > nleft) { + # Entire instruction is not yet present in buffer. + TR_IP(tr) = ip + return (EOF) + } else { + # Entire instruction is present in buffer. + TR_IP(tr) = ip + length + gki = ip + return (length) + } + } +end -- cgit