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\ Hypervisor Software File: fentry9.fth
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id: @(#)fentry9.fth 1.9 07/06/05
copyright: Copyright 2007 Sun Microsystems, Inc. All Rights Reserved
copyright: Use is subject to license terms.
\ Processor-dependent code to establish the proper machine state when
\ Forth is called from C. This is used by the "make-c-entry" routine
\ in makecentry.fth. These files are separate because the "make-c-entry"
\ routine is a compilation word which is somewhat different between the
\ metacompiler environment and the native compilation environment.
\ The implementation might be easier if Forth used the local registers for
\ its pointers, instead of the global registers. The outs could be
\ used for scratch registers instead of the locals.
tos %i0 move \ Return value (if any)
\ We don't want to depend on the data
\ stack pointer being the same, because
\ the routine may have left a return value
%o6 V9_SP_BIAS d# 16 na+ sp nget
\ Restore these in case of multiple levels of cross-language calls;
\ if the Forth word that was just executed called a C subroutine,
\ then saved-sp and saved-rp could have been changed.
%o6 V9_SP_BIAS d# 17 na+ %g1 nget
%o6 V9_SP_BIAS d# 18 na+ %g2 nget
%o6 V9_SP_BIAS d# 19 na+ %g3 nget
%o6 V9_SP_BIAS d# 20 na+ %g4 nget
%o6 V9_SP_BIAS d# 21 na+ %g5 nget
%o6 V9_SP_BIAS d# 22 na+ %g6 nget
%o6 V9_SP_BIAS d# 23 na+ %g7 nget
\ This is used in only one place -- the implementation of the op_release
\ ROMvec entry. It pops a call frame and returns to the caller's caller.
\ This is a special-purpose hack used to implement "kill a process from
code double-return-to-c ( -- )
\ We don't want to depend on the data
\ stack pointer being the same, because
\ the routine may have left a return value
%o6 V9_SP_BIAS d# 16 na+ sp nget
\ Restore these in case of multiple levels of cross-language calls;
\ if the Forth word that was just executed called a C subroutine,
\ then saved-sp and saved-rp could have been changed.
%o6 V9_SP_BIAS d# 17 na+ %g1 nget
%o6 V9_SP_BIAS d# 18 na+ %g2 nget
%o6 V9_SP_BIAS d# 19 na+ %g3 nget
%o6 V9_SP_BIAS d# 20 na+ %g4 nget
%o6 V9_SP_BIAS d# 21 na+ %g5 nget
%o6 V9_SP_BIAS d# 22 na+ %g6 nget
%o6 V9_SP_BIAS d# 23 na+ %g7 nget
%g0 0 %g0 restore \ Remove the caller's stack frame
%i7 8 %g0 jmpl \ Return to the caller's caller
\ We get here from a Forth C-entry stub, which in turn was called from a
\ C subroutine call. The entry stub did a "save", then called forth-entry.
\ The IP will be set to the location following the delay slot of the call.
\ The "save" allocated enough space for saving the window registers (16 x 8),
\ plus the globals (8 x 8), plus space for 2 Forth stacks (64+64).
\ We have a fresh set of local registers as a result of the save.
\ The arguments are in the caller's "out" registers, which are our "in"
\ registers after we do the "save", which also gets us a fresh set of locals.
\ Save the globals on the stack
%g1 %o6 V9_SP_BIAS d# 17 na+ nput
%g2 %o6 V9_SP_BIAS d# 18 na+ nput
%g3 %o6 V9_SP_BIAS d# 19 na+ nput
%g4 %o6 V9_SP_BIAS d# 20 na+ nput
%g5 %o6 V9_SP_BIAS d# 21 na+ nput
%g6 %o6 V9_SP_BIAS d# 22 na+ nput
%g7 %o6 V9_SP_BIAS d# 23 na+ nput
\ Establish a Forth execution environment by setting the values of
\ the Forth virtual machine registers base, up, ip, rp, and sp.
\ Set the interpret pointer to the word this Forth entry is to execute
dictionary-size ( offset )
here 8 + call \ address of next instruction in spc
( offset ) base set \ relative address of current instruction
spc base base sub \ subtract them to find the base address
'body main-task tos set \ Allow the exception handler to find the
%o0 6 %o2 lduh \ main user area in the "constant" main-task
%o0 4 up lduh \ main user area in the "constant" main-task
'user saved-sp %o2 nget \ Establish the Return Stack
%o2 %o6 V9_SP_BIAS d# 16 na+ nput \ For restoring saved-sp upon return
'user saved-rp %o3 nget \ Establish the Parameter Stack
%o3 %o6 V9_SP_BIAS d# 24 na+ nput \ For restoring saved-rp upon return
\ To make Forth re-entrant, we allocate space on the stacks in case
\ Forth gets called again by an interrupt handler.
%o2 h# 40 /n* %l0 sub \ Allocate some space on the Parameter Stack
%o3 h# 40 /n* %l0 sub \ Allocate some space on the Return Stack
\ Pass up to 6 subroutine arguments to Forth
\ Now we can blow away our in regs
\ Align adr so that the data segment will start at the right place.
\ Depending on the machine architecture, the Sun loader aligns the
\ data segment on a particular boundary. For the SPARC, the alignment
\ boundary is a doubleword (8 bytes).
: align-data ( adr -- aligned-adr ) 7 + -8 and ;
d# 16 /n* ( window registers ) 8 /n* ( global registers ) + /n + ( rp )
negate constant /entry-frame
projects / OpenSPARC-T2-SAM / blob