Initial revision

lang/pc/libpc/gto.e

@@ -0,0 +1,84 @@
+#
+;  (c) copyright 1983 by the Vrije Universiteit, Amsterdam, The Netherlands.
+; 
+;           This product is part of the Amsterdam Compiler Kit.
+; 
+;  Permission to use, sell, duplicate or disclose this software must be
+;  obtained in writing. Requests for such permissions may be sent to
+; 
+;       Dr. Andrew S. Tanenbaum
+;       Wiskundig Seminarium
+;       Vrije Universiteit
+;       Postbox 7161
+;       1007 MC Amsterdam
+;       The Netherlands
+; 
+
+/* Author: J.W. Stevenson */
+
+
+ mes 2,EM_WSIZE,EM_PSIZE
+
+#define TARLB   0
+#define DESCR   EM_PSIZE
+
+#define NEWPC   0
+#define SAVSP   EM_PSIZE
+
+#define D_PC    0
+#define D_SP    EM_PSIZE
+#define D_LB    EM_PSIZE+EM_PSIZE
+
+#define LOCLB   -EM_PSIZE
+
+; _gto is called with two arguments:
+;       - pointer to the label descriptor (DESCR)
+;       - local base (LB) of target procedure (TARLB)
+; the label descriptor contains two items:
+;       - label address i.e. new PC (NEWPC)
+;       - offset in target procedure frame (SAVSP)
+; using this offset and the LB of the target procedure, the address of
+; of local variable of the target procedure is constructed.
+; the target procedure must have stored the correct target SP there.
+
+descr
+ bss 3*EM_PSIZE,0,0
+
+ exp $_gto
+ pro $_gto,EM_PSIZE
+ lal DESCR
+ loi EM_PSIZE
+ adp NEWPC
+ loi EM_PSIZE
+ lae descr+D_PC
+ sti EM_PSIZE
+ lal TARLB
+ loi EM_PSIZE
+ zer EM_PSIZE
+ cmp
+ zeq *1
+ lal TARLB
+ loi EM_PSIZE
+ bra *2
+1
+ lae _m_lb
+ loi EM_PSIZE
+2
+ lal LOCLB
+ sti EM_PSIZE
+ lal LOCLB
+ loi EM_PSIZE
+ lal DESCR
+ loi EM_PSIZE
+ adp SAVSP
+ loi EM_WSIZE           ; or EM_PSIZE ?
+ ads EM_WSIZE           ; or EM_PSIZE ?
+ loi EM_PSIZE
+ lae descr+D_SP
+ sti EM_PSIZE
+ lal LOCLB
+ loi EM_PSIZE
+ lae descr+D_LB
+ sti EM_PSIZE
+ gto descr
+ end ?