subttl  Structure definitions
	  page

; Data structures in the child's space

; File block
file_block struc
fb_id	  dw	  ?		   ;ID
fb_flags  dw	  ?		   ;flags
fb_lut	  dw	  ?,?		   ;lookup table@ (far)
fb_pb	  dw	  ?,?		   ;parameter block@ (far)
fb_reserved dw	  8 dup (?)	   ;reserved
file_block ends
;
fb_dummy       equ  fb_reserved	   ;dummy for now
fb_sysint_addr equ  fb_reserved+2  ;system code (far @ of entry routine)

; Parameter block
parm_block struc
pb_select      dw ?		   ;lookup table entry maps to number
pb_ss	       dw ?		   ;special services
pb_ss_args     dw 8 dup (?)	   ;special service arguments
pb_reserved    dw 8 dup (?)	   ;reserved
pb_rvtype      dw ?		   ;return value type
pb_rv	       dw 4 dup (?)	   ;return value
pb_args        dw ?		   ;beginning of passed parameters
parm_block ends

; Local structures

; The context we will remember for parent or child
state	  struc
st_ds	  dw	  0
st_es	  dw	  0
st_ss	  dw	  0
st_sp	  dw	  0
st_bp	  dw	  0
state	  ends

; The child's stack at the point it called us
cstack	  struc
cs_ret	  dw	  0,0		   ;far return address
cs_len	  dw	  0		   ;child's length
cs_psp	  dw	  0		   ;child's PSP
cstack	  ends

; String search temporary structure
search_struc struc
srch_exe   dw	  0		   ;# of child being tested
srch_dptr  dw	  0,0		   ;seg:offset of child's string
srch_sptr  dw	  0,0		   ;seg:offset of parent's string
srch_slen  dw	  0		   ;#chars in Scheme string
search_struc ends

; Swap structure
swap_struc struc
sw_reg	  dw	  0		   ;VM register containing this argument
sw_offset dw	  0		   ;argument's final location (after
				   ;packing, etc) in parm block
swap_struc ends

; Information needed during one xesc call
xesc_struc struc
xs_rvptr  dw	  0,0		   ;return value@ (far)
xs_args   dw	  0,0		   ;first arg@ (far)
xs_local  dw	  0,0		   ;work area@ (far)
xs_dest   dw	  0,0		   ;copy data to this dest@ (far)
xs_pc	  dw	  0,0		   ;bytecode@ into xesc instruction (far)
xs_select dw	  0		   ;name converted to this number
xs_flags  dw	  0		   ;flags
xs_nargs  dw	  0		   ;actual #args in current call
xs_rvtype dw	  0		   ;return value type
xs_rvreg  dw	  0		   ;return value goes into this VM register
xs_pb_segment dw  0		   ;segment address of parm block
C_fn	  dw	  ?		   ;used during far calls to our C routines
C_retadr  dw	  ?,?
xesc_struc ends