! Patch to TTDRIVER to enable statistics collection

DEFINE PMS$GL_DOSTATS = 80002E84
DEFINE PMS$AL_READTBL = 80002E08
DEFINE PMS$GL_TREADS = 80002DB8
DEFINE PMS$GL_READCNT = 80002E58
DEFINE PMS$AL_WRITETBL = 80002E30
DEFINE PMS$GL_TWRITES = 80002DBC
DEFINE PMS$GL_WRTCNT = 80002E5C
DEFINE IRP$V_FCODE = 0
DEFINE IRP$S_FCODE = 6
DEFINE IRP$W_FUNC = 20
DEFINE IRP$W_BCNT = 32
DEFINE TTY$C_FC_READ = 0

VERIFY/WORD 8 = 2328
SET PATCH/INIT=87 2328

DEFINE TTYSTRSTP = 7F4

ALIGN/BYTE TT_STAT_PAT
DEPOSIT/INST/PATCH TT_STAT_PAT
'MOVL	R5,R3'
'BRB	PAT_2$'
'PAT_1$: MOVL	R4,R3'		! include replaced instruction
'PAT_2$: BLBC	@#PMS$GL_DOSTATS,PAT_40$' ! if flag set, bypass stat code
'MOVZWL	B^IRP$W_BCNT(R3),R1'
'DIVL3	#5,R1,R0'
'CMPL	#9,R0'
'BGEQ	PAT_10$'
'MOVL	#9,R0'
'PAT_10$: CMPZV	#IRP$V_FCODE,#IRP$S_FCODE,B^IRP$W_FUNC(R3),#TTY$C_FC_READ'
'BNEQ	PAT_20$'
'INCL	@#PMS$AL_READTBL[R0]'
'INCL	@#PMS$GL_TREADS'
'ADDL2	R1,@#PMS$GL_READCNT'
'BRB	PAT_40$'
'PAT_20$:	INCL	@#PMS$AL_WRITETBL[R0]'
'INCL	@#PMS$GL_TWRITES'
'ADDL2	R1,@#PMS$GL_WRTCNT'
'PAT_40$:	RSB'
EXIT

REPLACE/INST TTYSTRSTP+4C9
'MOVL	R5,R3'		! place to include performance monitoring
EXIT
'BSBW	TT_STAT_PAT'	! branch to new collection code
EXIT

REPLACE/INST TTYSTRSTP+557
'MOVL	R4,R3'		! place to include performance monitoring
EXIT
'BSBW	PAT_1$'	! branch to new collection code
EXIT

ALIGN/BYTE TT_STAT_SIZE
REPLACE/WORD 8
2328
EXIT
TT_STAT_SIZE
EXIT

UPDATE

EXIT