NetBSD/sys/arch/x68k/stand/common/start.S

482 lines
8.4 KiB
ArmAsm

|-----------------------------------------------------------
|
| Simple C runtime startup for Human68k
|
| o no stdio support (DOS/IOCS only)
| o HUPAIR support
|
| written by Yasha (ITOH Yasufumi)
|
| This file is in the public domain
|
| $NetBSD: start.S,v 1.1 1998/09/01 19:51:56 itohy Exp $
|-----------------------------------------------------------
|
| configuration
|
#ifndef STACK_SIZE
#define STACK_SIZE 65536 /* stack size in bytes */
#endif
#ifndef STACK_SYMBOL
#define STACK_SYMBOL stack_8K_hUMAn6 /* has largest hash val on NetBSD ld */
#endif /* and will be at the end of bss */
#ifndef DUMMY___main
#define DUMMY___main 1 /* dummy __main() */
#endif
#ifndef SUPPORT_R_EXEC /* support ".r" relocatable executable */
#define SUPPORT_R_EXEC 0 /* (clear bss, don't use a1 at startup) */
#endif /* XXX impossible for a.out */
#ifndef SUPPORT_HUPAIR
#define SUPPORT_HUPAIR 1 /* HUPAIR argument interface support */
#endif
#ifndef HUPAIR_ARGV0
#define HUPAIR_ARGV0 1 /* use argv[0] passed in HUPAIR manner */
#endif
#ifndef ADD_PATHNAME
#define ADD_PATHNAME 0 /* add command path to argv[0] if not HUPAIR */
#endif
#ifndef STRICT_SETBLOCK
#define STRICT_SETBLOCK 1 /* free unused memory after creating args */
#endif
#ifndef C_REGPARM
#define C_REGPARM 0 /* main() arguments are passed in registers */
#endif /* (for gcc -mregparm) */
#ifndef NEED_MEMCP
#define NEED_MEMCP 0 /* __memcp: MCB address */
#endif
#ifndef NEED_PROCP
#define NEED_PROCP 0 /* __procp: PDB address */
#endif
#ifndef NEED_VERNUM
#define NEED_VERNUM 1 /* __vernum: Human68k version */
#endif
#ifndef NEED_PROGNAME
#define NEED_PROGNAME 1 /* ___progname: program basename */
#endif
#ifndef NEED_ENVIRON
#define NEED_ENVIRON 1 /* _environ: environment vector */
#endif
|-----------------------------------------------------------
|
| DOS call
|
#define DOS(x) .word x
#define __FPUTS 0xFF1E
#define __VERNUM 0xFF30
#define __SETBLOCK 0xFF4A
#define __EXIT2 0xFF4C
|
| seed to estimate argument string/vector and environment vector size
| (max nohupair argv[0](92+4) + NULLs(8) + alignment(3)) <- donburi?
|
#define estimated_argsz 107
#define estimated_com 92 /* estimated command name length (included) */
|
| other constants
|
#define char_tab 0x09
#define char_space 0x20
#define char_dquote 0x22
#define char_squote 0x27
#define char_slash 0x2f
#define char_backslash 0x5c
#define pdb_mcb 0x10 /* PDB address - MCB address */
#define drvpath_pdb 0x070 /* drive and path address - PDB address */
#define command_pdb 0x0b4 /* command name address - PDB address */
#define top_pdb 0xf0 /* program load address - PDB address */
#define stderr 2 /* stderr file handle */
#define exit_nomem 127 /* exit status on SETBLOCK failure */
|-----------------------------------------------------------
|
| execution start
|
| a0: MCB address, a1: program end + 1,
| a2: command line, a3: environ, a4: execution start
|
|.cpu 68000
.text
.even
.globl start,_main
start:
#if SUPPORT_HUPAIR
.word 0x611e,0x2348,0x5550,0x4149,0x5200
#else
.word 0x6016
#endif
#if SUPPORT_R_EXEC
.word 0x7263
#else
.word 0x7863
#endif
.long 0x72743020,0x56312E31,0x42206279,0x20596173,0x68610000
|
| check if hupair
|
#if SUPPORT_HUPAIR
moveal a7@+,a4
lea a2@(-8),a6
moveql #7,d3
chkhupair:
cmpmb a6@+,a4@+
dbne d3,chkhupair
| d3.l: 0xFFFF: hupair, 0x000x: not hupair
addqw #1,d3
beqs ishupair
#endif
moveql #char_tab,d3 | tab (= 9)
ishupair: | d3.l: 0: hupair, 9: not hupair
|
| (over)estimate and allocate argument/environ area beforehand
|
addql #1,a2 | skip byte count
moveql #estimated_argsz,d1 | byte counter
moveal a2,a6
moveql #char_space,d4 | space
acou1: addql #1,d1
moveb a6@+,d0
beqs acou2
cmpb d4,d0 | space
beqs acous
cmpb d3,d0 | tab (if not hupair)
bnes acou1
acous: addql #4,d1 | for argv area
bras acou1
acou2:
#if SUPPORT_HUPAIR && HUPAIR_ARGV0
tstb d3
bnes anohp
moveql #-estimated_com,d2 | reset argv[0] length
moveal a6,a4 | preserve argv[0] string address
acouhp: addql #1,d2
tstb a6@+
bnes acouhp
addl d2,d1
anohp:
#endif
| d1: estimated argument bytes
#if NEED_ENVIRON
addql #4,a3 | skip length field
moveal a3,a6
ecou1: addql #4,d1
tstb a6@+
beqs ecoue
ecou2: tstb a6@+
bnes ecou2
bras ecou1
ecoue:
#endif
| d1: estimated byte count
|
| free memory
| and ensure the bss/stack (for .r executable) and argument areas valid
|
lea a0@(pdb_mcb),a5 | a5: PDB address
subl a5,d1
#if SUPPORT_R_EXEC
#define RELOC(sym, reg) lea sym+top_pdb,reg; addl a5,reg
moveal a1,a6 | end of data
RELOC(_end, a1) | end of bss
#endif
pea a1@(0,d1:l) | _end + size - pdb
movel a5,a7@-
DOS(__SETBLOCK)
tstl d0
bpls sbnoerr
setblock_err:
movew #stderr,a7@
bsrs sberr1 | pea pc@
.asciz "setblock failed\r\n"
.even
sberr1: DOS(__FPUTS)
movew #exit_nomem,a7@
DOS(__EXIT2) | _exit(exit_nomem)
sbnoerr:
| here, the bss, stack, and argument/environ areas are certainly valid
|
| set stack
|
moveal #STACK_SYMBOL+STACK_SIZE,a7
#if SUPPORT_R_EXEC
|
| clear bss section
|
loop_clrbss:
clrl a6@+
cmpal a1,a6
bcss loop_clrbss
#endif
|
| save MCB address
|
#if NEED_MEMCP
# if SUPPORT_R_EXEC
RELOC(__memcp, a6)
movel a0,a6@
# else
movel a0,__memcp
# endif
#endif
|
| save PDB address
|
#if NEED_PROCP
# if SUPPORT_R_EXEC
RELOC(__procp, a6)
movel a5,a6@
# else
movel a5,__procp
# endif
#endif
|
| get version no of Human
|
#if NEED_VERNUM
DOS(__VERNUM)
# if SUPPORT_R_EXEC
RELOC(__vernum, a6)
movel d0,a6@
# else
movel d0,__vernum
# endif
#endif
|
| create argv[0]
|
moveal a1,a0 | top of argument strings
#if SUPPORT_HUPAIR && HUPAIR_ARGV0
tstb d3
beqs arg0lp
#endif
#if ADD_PATHNAME
lea a5@(drvpath_pdb),a4 | drive and path name
arg0path:
moveb a4@+,a1@+
bnes arg0path
subql #1,a1 | remove nul char
#endif
lea a5@(command_pdb),a4 | command name
arg0lp: moveb a4@+,a1@+
bnes arg0lp
#if NEED_PROGNAME
|
| find program basename
|
moveal a1,a4
prognlp:
cmpal a0,a4
beqs prognexit
moveb a4@-,d0
cmpib #char_slash,d0
beqs prognfou
cmpib #char_backslash,d0
bnes prognlp
prognfou:
addql #1,a4 | next of slash
prognexit:
# if SUPPORT_R_EXEC
RELOC(___progname, a6)
movel a4,a6@
# else
movel a4,___progname
# endif
#endif
|
| create argument strings
|
moveql #1,d0 | (d0:l) # arg
spskip: moveb a2@+,d2
beqs comline_end
cmpb d4,d2 | space
beqs spskip
cmpb d3,d2 | tab (if not hupair)
beqs spskip
| create an arg
clrb d1 | no quote here
addql #1,d0 | increment argc
arglp: tstb d1
bnes in_quote
cmpib #char_dquote,d2
beqs quote
cmpib #char_squote,d2
bnes notquote
quote: moveb d2,d1 | save quote character
bras argnextc
in_quote:
cmpb d1,d2
bnes argcopyc
clrb d1 | quote ended
bras argnextc
notquote:
cmpb d4,d2 | space
beqs arg_end
cmpb d3,d2 | tab (if not hupair)
bnes argcopyc
arg_end:
clrb a1@+
bras spskip
argcopyc:
moveb d2,a1@+ | copy char
argnextc:
moveb a2@+,d2
bnes arglp
clrb a1@+
comline_end:
|
| create argv vector
|
addql #3,a1
movel a1,d1
andib #0xfc,d1 | long alignment
moveal d1,a1 | argv
movel d0,d4 | argc
| a0 is at argument strings
mkargv:
movel a0,a1@+ | argv[0] ...
nxtarg: tstb a0@+
bnes nxtarg
#if STRICT_SETBLOCK
subqw #1,d0
#else
subqw #1,d4
#endif
bnes mkargv
clrl a1@+ | argv[argc] should be NULL
|
| create envp vector
|
#if NEED_ENVIRON
movel a1,d2
envlp: tstb a3@
beqs envend
movel a3,a1@+
envskp: tstb a3@+
bnes envskp
bras envlp
envend: clrl a1@+ | NULL termination
# if SUPPORT_R_EXEC
RELOC(_environ, a0)
movel d2,a0@
# else
movel d2,_environ
# endif
#endif
|
| free unused memory
|
#if STRICT_SETBLOCK
subal a5,a1
movel a1,a7@-
movel a5,a7@-
DOS(__SETBLOCK) | reset donburi-kanjo (never fails)
addql #8,a7
movel d4,d0 | argc
#endif
|
| make parameter
|
#if NEED_ENVIRON
movel d2,a7@- | arg #3 --- envp
#endif
#if !C_REGPARM
movel d1,a7@- | arg #2 --- argv
movel d0,a7@- | arg #1 --- argc
#endif
#if SUPPORT_R_EXEC
RELOC(_main, a0)
jsr a0@
#else
jsr _main
#endif
#if !C_REGPARM || NEED_ENVIRON
movew d0,a7@
#else
movew d0,a7@-
#endif
DOS(__EXIT2)
#if DUMMY___main
.globl ___main
___main:
rts
#endif
|-----------------------------------------------------------
|
| variables
|
#if NEED_MEMCP
.comm __memcp,4
#endif
#if NEED_PROCP
.comm __procp,4 | PDB address
#endif
#if NEED_VERNUM
.comm __vernum,4
#endif
#if NEED_PROGNAME
.comm ___progname,4
#endif
#if NEED_ENVIRON
.comm _environ,4 | environ address
#endif
|-----------------------------------------------------------
|
| stack
|
.comm STACK_SYMBOL,STACK_SIZE