commit a0189ddbc8638e2a16885e73116680ee531ff334
parent 2dc039bdab1df0ca70af7b1dedd6b46ddf5607bd
Author: Virgil Dupras <hsoft@hardcoded.net>
Date: Sun, 5 Mar 2023 13:18:34 -0500
asm/i386: have pspush, and pspop, macros take opmod arguments
Diffstat:
5 files changed, 114 insertions(+), 128 deletions(-)
diff --git a/fs/asm/i386.fs b/fs/asm/i386.fs
@@ -56,10 +56,6 @@ create _bank $10 CELLSZ * allot
: bank@ ( opmod -- n ) bankid@ bank' @ ;
: newbankedop ( n -- opmod ) newbankid tuck bank' ! 20 lshift ;
-\ MOD/RM constants
-0 const AX 1 const CX 2 const DX 3 const BX
-4 const SP 5 const BP 6 const SI 7 const DI
-
: r) $1c0 or 1 to+ _argcnt ;
: _ doer ( reg -- ) , does> @ ( reg ) $c0 or 1 to+ _argcnt ;
@@ -259,8 +255,7 @@ $e2 op loop, $e1 op loopz, $e0 op loopnz,
: [esi] si 0 d) ;
: ps+, bp CELLSZ i) sub, ;
: ps-, bp CELLSZ i) add, ;
-: pspush, ( regid -- ) ps+, [ebp] swap $100 or r) mov, ;
-: pspushN, ( n -- ) ps+, [ebp] swap i) mov, ;
-: pspop, ( regid -- ) $100 or r) [ebp] mov, ps-, ;
-\ equivalent to r1 pspop, then r2 pspop,
-: pspop2, ( r1 r2 -- ) $100 or r) bp CELLSZ d) mov, $100 or r) [ebp] mov, bp CELLSZ << i) add, ;
+: pspush, ( opmod -- ) ps+, [ebp] swap mov, ;
+: pspop, ( opmod -- ) [ebp] mov, ps-, ;
+\ equivalent to op1 pspop, then op2 pspop,
+: pspop2, ( op1 op2 -- ) bp CELLSZ d) mov, r) [ebp] mov, bp CELLSZ << i) add, ;
diff --git a/fs/comp/c/vm/i386.fs b/fs/comp/c/vm/i386.fs
@@ -12,6 +12,9 @@
$cb const USABLEREGS \ 11001011 = di si bx cx ax
0 value regused \ a bit mask of register used.
+\ i386 register ID constants
+0 const AX 1 const CX 2 const DX 7 const DI
+
: regusable? ( regid -- f ) USABLEREGS swap bit? ;
: regused? ( regid -- f ) regused swap bit? ;
: reguse ( regid -- )
diff --git a/fs/doc/asm/i386.txt b/fs/doc/asm/i386.txt
@@ -37,18 +37,6 @@ cr0 cr2 cr3
dr0 dr1 dr2 dr3 dr6 dr7
tr6 tr7
-## Dynamic register operand
-
-If you want to specify a register in a dynamic manner, you can use the uppercase
-versions of those registers specified below (which are simple constants that
-yield the values to be encoded in the opcode) and use the "opreg!" word. For
-example:
-
-create mylist DX c, SI c, BP c,
-mylist 2 + c@ r) inc,
-
-would result in the equivalent of "bp inc," being written
-
## Immediate operand
i) ( imm -- )
diff --git a/fs/xcomp/i386/kernel.fs b/fs/xcomp/i386/kernel.fs
@@ -41,56 +41,56 @@ L1 forward!
lblidt m) lidt, sti,
forward16 jmp, to L1
-xcode IDT L2 pspushN, ret,
-xcode CALLSZ 5 pspushN, ret,
-xcode BRSZ 5 pspushN, ret,
-xcode ?BRSZ 14 pspushN, ret,
+xcode IDT L2 i) pspush, ret,
+xcode CALLSZ 5 i) pspush, ret,
+xcode BRSZ 5 i) pspush, ret,
+xcode ?BRSZ 14 i) pspush, ret,
xcode noop pc to lblret ret,
xcode (cell)
ax pop,
- AX pspush,
+ ax pspush,
ret,
xcode (does)
ax pop,
bx ax mov,
bx CELLSZ i) add,
- BX pspush,
+ bx pspush,
ax 0 d) jmp,
xcode (s)
si pop, \ addr of str
- SI pspush,
+ si pspush,
ax ax xor,
lodsb, \ len
si ax add, \ ret to PC right after str
si jmp,
xcode herestart
- HERESTART pspushN,
+ HERESTART i) pspush,
ret,
pc HEREMAX ,
xcode HEREMAX
- ( pc ) pspushN,
+ ( pc ) i) pspush,
ret,
pc to lblhere HERESTART ,
xcode HERE
- lblhere pspushN,
+ lblhere i) pspush,
ret,
pc to lblsysdict 0 , 0 c, \ 1b zero len field. see doc/arch
xcode sysdict
- lblsysdict pspushN,
+ lblsysdict i) pspush,
ret,
pc to lblcompiling 0 ,
xcode compiling
ax lblcompiling m) mov,
- AX pspush,
+ ax pspush,
ret,
xcode quit
@@ -110,12 +110,12 @@ xcode exit
ret,
xcode execute
- AX pspop,
+ ax pspop,
ax jmp,
xcode dup ( a -- a a )
ax [ebp] mov,
- AX pspush,
+ ax pspush,
ret,
xcode ?dup ( a -- a? a )
@@ -132,7 +132,7 @@ xcode swap ( a b -- b a )
xcode over ( a b -- a b a )
ax bp CELLSZ d) mov,
- AX pspush,
+ ax pspush,
ret,
xcode rot ( a b c -- b c a )
@@ -145,7 +145,7 @@ xcode rot ( a b c -- b c a )
ret,
xcode nip ( a b - b )
- AX pspop,
+ ax pspop,
[ebp] ax mov,
ret,
@@ -154,7 +154,7 @@ xcode tuck ( a b -- b a b )
bx bp CELLSZ d) mov,
[ebp] bx mov,
bp CELLSZ d) ax mov,
- AX pspush,
+ ax pspush,
ret,
xcode rot> ( a b c -- c a b )
@@ -170,7 +170,7 @@ xcode scnt
ax PSTOP i) mov,
ax bp sub,
ax 16b) 2 i) shr, \ div by 4, preserve neg
- AX pspush,
+ ax pspush,
ret,
xcode rcnt
@@ -178,7 +178,7 @@ xcode rcnt
ax sp sub,
ax 16b) 2 i) shr, \ div by 4, preserve neg
ax dec, \ ignore this call
- AX pspush,
+ ax pspush,
ret,
xcode 1+
@@ -190,17 +190,17 @@ xcode 1-
ret,
xcode +
- AX pspop,
+ ax pspop,
[ebp] ax add,
ret,
xcode -
- AX pspop,
+ ax pspop,
[ebp] ax sub,
ret,
xcode *
- AX pspop,
+ ax pspop,
[ebp] mul,
[ebp] ax mov,
ret,
@@ -214,39 +214,39 @@ xcode /mod ( a b -- r q )
ret,
xcode <<c
- 0 pspushN,
+ 0 i) pspush,
bp CELLSZ d) 1 i) shl,
[ebp] setc,
ret,
xcode >>c
- 0 pspushN,
+ 0 i) pspush,
bp CELLSZ d) 1 i) shr,
[ebp] setc,
ret,
xcode lshift ( n u -- n )
- CX pspop,
+ cx pspop,
[ebp] cl shl,
ret,
xcode rshift ( n u -- n )
- CX pspop,
+ cx pspop,
[ebp] cl shr,
ret,
xcode and
- AX pspop,
+ ax pspop,
[ebp] ax and,
ret,
xcode or
- AX pspop,
+ ax pspop,
[ebp] ax or,
ret,
xcode xor
- AX pspop,
+ ax pspop,
[ebp] ax xor,
ret,
@@ -265,7 +265,7 @@ xcode not
ret,
xcode <
- AX pspop,
+ ax pspop,
[ebp] ax sub,
[ebp] 0 i) mov,
[ebp] setc,
@@ -293,36 +293,36 @@ xcode @ ( a -- n )
ret,
xcode c!
- AX BX pspop2, \ ax=a bx=n
+ ax bx pspop2, \ ax=a bx=n
ax 0 d) bl mov,
ret,
pc 0 , EMETA_8B ,
xwordlbl c! absjmp,
pc nextmeta ! ( pc ) , EMETA_16B ,
- AX BX pspop2, \ ax=a bx=n
+ ax bx pspop2, \ ax=a bx=n
ax 0 d) 16b) bx mov,
ret,
xcode ! ( n a -- )
- AX BX pspop2, \ ax=a bx=n
+ ax bx pspop2, \ ax=a bx=n
ax 0 d) bx mov,
ret,
pc 0 , EMETA_8B ,
- AX BX pspop2, \ ax=a bx=n
+ ax bx pspop2, \ ax=a bx=n
ax 0 d) bl add,
ret,
pc nextmeta ! ( pc ) , EMETA_16B ,
- AX BX pspop2, \ ax=a bx=n
+ ax bx pspop2, \ ax=a bx=n
ax 0 d) 16b) bx add,
ret,
xcode +! ( n a -- )
- AX BX pspop2, \ ax=a bx=n
+ ax bx pspop2, \ ax=a bx=n
ax 0 d) bx add,
ret,
xcode c,
- AX pspop, \ ax=n
+ ax pspop, \ ax=n
pc to lblcwrite \ al=c preserves bx
si lblhere m) mov,
[esi] al mov,
@@ -332,13 +332,13 @@ pc to lblcwrite \ al=c preserves bx
pc 0 , EMETA_8B ,
xwordlbl c, absjmp,
pc nextmeta ! ( pc ) , EMETA_16B ,
- AX pspop, \ ax=n
+ ax pspop, \ ax=n
si lblhere m) mov,
[esi] 16b) ax mov,
lblhere m) 2 i) add,
ret,
xcode ,
- AX pspop, \ ax=n
+ ax pspop, \ ax=n
pc to lblwrite \ ax=n
si lblhere m) mov,
[esi] ax mov,
@@ -353,7 +353,7 @@ xcode pc@ ( port -- n8 )
ret,
xcode pc! ( n8 port -- )
- DX AX pspop2,
+ dx ax pspop2,
al dx out,
ret,
@@ -365,7 +365,7 @@ xcode pw@ ( port -- n16 )
ret,
xcode pw! ( n16 port -- )
- DX AX pspop2,
+ dx ax pspop2,
ax 16b) dx out,
ret,
@@ -377,20 +377,20 @@ xcode p@ ( port -- n32 )
ret,
xcode p! ( n32 port -- )
- DX AX pspop2,
+ dx ax pspop2,
ax dx out,
ret,
xcode move ( src dst u -- )
- CX pspop,
- DI SI pspop2,
+ cx pspop,
+ di si pspop2,
cx cx test,
lblret abs>rel jz,
rep, movsb,
ret,
xcode move, ( src u -- )
- CX SI pspop2,
+ cx si pspop2,
cx cx test,
lblret abs>rel jz,
pc to lblmovewrite \ esi=a ecx=u
@@ -400,7 +400,7 @@ pc to lblmovewrite \ esi=a ecx=u
ret,
xcode []= ( a1 a2 u -- f )
- CX DI pspop2,
+ cx di pspop2,
si [ebp] mov,
ax ax xor,
repz, cmpsb,
@@ -409,7 +409,7 @@ xcode []= ( a1 a2 u -- f )
ret,
xcode align4 ( n -- )
- AX pspop,
+ ax pspop,
ax lblhere m) add,
ax 3 i) and,
lblret abs>rel jz,
@@ -419,20 +419,20 @@ xcode align4 ( n -- )
pc to lbl[rcnt] 0 ,
xcode [rcnt]
- lbl[rcnt] pspushN,
+ lbl[rcnt] i) pspush,
ret,
pc 2 nc, $83 $c4 ( XX ) \ sp XX i) add,
xcode r+, ( n -- )
( pc ) 2 movewrite,
- AX pspop,
+ ax pspop,
lbl[rcnt] m) ax add,
lblcwrite absjmp,
pc 2 nc, $83 $c5 ( XX ) \ bp XX i) add,
xcode p+, ( n -- )
( pc ) 2 movewrite,
- AX pspop,
+ ax pspop,
lblcwrite absjmp,
pc 3 nc, $58 $ff $d0 \ ax pop, ax call,
@@ -446,8 +446,8 @@ xcode rtype xwordlbl (abort) absjmp,
\ through boot<.
pc ," boot failure"
xcode abort
- ( pc ) pspushN,
- 12 pspushN,
+ ( pc ) i) pspush,
+ 12 i) pspush,
wcall, rtype
0 jmp,
@@ -456,7 +456,7 @@ xcode boot<
si lblbootptr m) mov,
ax [esi] 8b) movzx,
lblbootptr m) inc,
- AX pspush,
+ ax pspush,
ret,
\ where "word" feeds itself
@@ -465,17 +465,17 @@ xcode in< xwordlbl boot< absjmp,
pc to lblnextword 0 ,
xcode NEXTWORD
- lblnextword pspushN,
+ lblnextword i) pspush,
ret,
pc to lblcurword $20 allot0
xcode curword
- lblcurword pspushN,
+ lblcurword i) pspush,
ret,
pc to L1 ( word_eof )
ax ax xor,
- AX pspush,
+ ax pspush,
ret,
pc \ we have a nonzero lblnextword
@@ -486,7 +486,7 @@ pc \ we have a nonzero lblnextword
cl inc,
di lblcurword i) mov,
rep, movsb,
- lblcurword pspushN,
+ lblcurword i) pspush,
ret,
xcode maybeword ( -- str-or-0 )
@@ -494,7 +494,7 @@ xcode maybeword ( -- str-or-0 )
( pc ) abs>rel jnz,
pc ( loop1 )
wcall, in<
- AX pspop,
+ ax pspop,
ax ax test,
L1 ( word_eof ) abs>rel js,
ax SPC 1+ i) cmp, \ is ws?
@@ -506,7 +506,7 @@ pc ( loop2 )
bx push,
wcall, in<
bx pop,
- AX pspop,
+ ax pspop,
ax ax test,
forward js, to L1 ( stoploop )
ax SPC 1+ i) cmp, \ is ws?
@@ -514,7 +514,7 @@ pc ( loop2 )
L1 forward! ( stoploop )
bx lblcurword 1+ i) sub,
lblcurword m) bl mov,
- lblcurword pspushN,
+ lblcurword i) pspush,
ret,
pc ," word expected"
@@ -525,13 +525,13 @@ xcode word
cx 13 i) mov,
si swap ( pc ) i) mov,
pc to lblerrmsg \ exc=sl esi=sa
- SI pspush,
- CX pspush,
+ si pspush,
+ cx pspush,
wcall, rtype
xwordlbl abort absjmp,
xcode findmeta ( id ll -- ll-or-0 )
- AX pspop,
+ ax pspop,
bx [ebp] mov,
pc to L1
ax ax test,
@@ -546,7 +546,7 @@ forward! forward!
pc to lblmod 0 ,
xcode MOD
- lblmod pspushN,
+ lblmod i) pspush,
ret,
xcode findmod ( w -- w )
@@ -555,9 +555,9 @@ xcode findmod ( w -- w )
ax [ebp] mov,
ax 9 i) sub,
bx lblmod m) mov,
- BX pspush, AX pspush,
+ bx pspush, ax pspush,
wcall, findmeta
- AX pspop,
+ ax pspop,
ax ax test,
forward8 jz,
lblmod m) 0 i) mov,
@@ -567,7 +567,7 @@ xcode findmod ( w -- w )
ret,
xcode find ( str 'dict -- word-or-0 )
- DX pspop,
+ dx pspop,
pc to lblfind
si [ebp] mov,
cx [esi] 8b) movzx,
@@ -600,9 +600,9 @@ L1 forward! ( skip1 )
pc ," word not found"
xcode (wnf)
- lblcurword 1+ pspushN,
+ lblcurword 1+ i) pspush,
cx lblcurword m) 8b) movzx,
- CX pspush,
+ cx pspush,
wcall, rtype
cx 15 i) mov,
si swap ( pc ) i) mov,
@@ -628,7 +628,7 @@ xcode ' ( "name" -- w )
ax ax xor,
al si 1 d) mov,
[ebp] ax mov,
- 1 pspushN,
+ 1 i) pspush,
ret,
0 align4 pc to lblparseh ( str -- n? f ) \ esi=sa ecx=sl
@@ -656,7 +656,7 @@ L2 forward! \ parse ok
si inc,
( pc ) abs>rel loop, ( loop )
[ebp] ax mov,
- 1 pspushN,
+ 1 i) pspush,
ret,
0 align4 pc to lblparseud ( str -- n? f ) \ esi=sa ecx=sl
@@ -675,7 +675,7 @@ pc ( loop )
si inc,
( pc ) abs>rel loop, ( loop )
[ebp] ax mov,
- 1 pspushN,
+ 1 i) pspush,
ret,
xcode parse ( str -- n? f )
@@ -721,7 +721,7 @@ pc
xcode ,"
wcall, "<
- AX pspop,
+ ax pspop,
ax ax test,
lblret abs>rel js,
xwordlbl ," i) push,
@@ -729,7 +729,7 @@ xcode ,"
pc to lblnextmeta 0 ,
xcode nextmeta
- lblnextmeta pspushN,
+ lblnextmeta i) pspush,
ret,
pc 6 nc, $83 $ed $04 $c7 $45 $00 ( XX ) \ bp 4 i) sub, [ebp] XX i) mov,
@@ -747,7 +747,7 @@ pc to lblrelwr \ ax=abs addr
lblwrite absjmp,
xcode execute,
- BX pspop,
+ bx pspop,
lblcallwr absjmp,
xcode exit,
@@ -756,25 +756,25 @@ xcode exit,
xcode branch,
al $e9 ( jmp ) i) mov, lblcwrite abscall,
- AX pspop,
+ ax pspop,
lblrelwr abscall,
ax lblhere m) mov,
ax 4 i) sub,
- AX pspush,
+ ax pspush,
ret,
-pc 10 nc, $8b $45 $00 $83 $c5 $04 $85 $c0 $0f $84 \ AX pspop, ax ax test, XX jz,
+pc 10 nc, $8b $45 $00 $83 $c5 $04 $85 $c0 $0f $84 \ ax pspop, ax ax test, XX jz,
xcode ?branch,
( pc ) 10 movewrite,
- AX pspop,
+ ax pspop,
lblrelwr abscall,
ax lblhere m) mov,
ax 4 i) sub,
- AX pspush,
+ ax pspush,
ret,
xcode branch!
- AX BX pspop2, \ ax=a bx=n
+ ax bx pspop2, \ ax=a bx=n
bx ax sub, \ displacement
bx 4 i) sub, \ ... from *after* call/jmp op
ax 0 d) bx mov,
@@ -812,37 +812,37 @@ xcode [A]+,
pc to L1 \ 8b A@
ax di 0 d) 8b) movzx,
- AX pspush,
+ ax pspush,
ret,
pc 0 , EMETA_8B ,
bx L1 i) mov, lblcallwr absjmp,
pc to L1 \ 16b A@
ax di 0 d) movzx,
- AX pspush,
+ ax pspush,
ret,
pc nextmeta ! ( pc ) , EMETA_16B ,
bx L1 i) mov, lblcallwr absjmp,
pc to L1 \ A@
ax di 0 d) mov,
- AX pspush,
+ ax pspush,
ret,
xcode A@,
bx L1 i) mov, lblcallwr absjmp,
pc to L1 \ 8b A!
- AX pspop,
+ ax pspop,
di 0 d) al mov,
ret,
pc 0 , EMETA_8B ,
bx L1 i) mov, lblcallwr absjmp,
pc to L1 \ 16b A!
- AX pspop,
+ ax pspop,
di 0 d) 16b) ax mov,
ret,
pc nextmeta ! ( pc ) , EMETA_16B ,
bx L1 i) mov, lblcallwr absjmp,
pc to L1 \ A!
- AX pspop,
+ ax pspop,
di 0 d) ax mov,
ret,
xcode A!,
@@ -873,19 +873,19 @@ xcode A@!,
bx L1 i) mov, lblcallwr absjmp,
pc to L1 \ 8b A+!
- AX pspop,
+ ax pspop,
di 0 d) al add,
ret,
pc 0 , EMETA_8B ,
bx L1 i) mov, lblcallwr absjmp,
pc to L1 \ 16b A+!
- AX pspop,
+ ax pspop,
di 0 d) 16b) ax add,
ret,
pc nextmeta ! ( pc ) , EMETA_16B ,
bx L1 i) mov, lblcallwr absjmp,
pc to L1 \ A+!
- AX pspop,
+ ax pspop,
di 0 d) ax add,
ret,
xcode A+!,
@@ -894,42 +894,42 @@ xcode A+!,
pc to L1 \ 8b [A]@
ax di 0 d) mov,
ax ax 0 d) 8b) movzx,
- AX pspush,
+ ax pspush,
ret,
pc 0 , EMETA_8B ,
bx L1 i) mov, lblcallwr absjmp,
pc to L1 \ 16b [A]@
ax di 0 d) mov,
ax ax 0 d) movzx,
- AX pspush,
+ ax pspush,
ret,
pc nextmeta ! ( pc ) , EMETA_16B ,
bx L1 i) mov, lblcallwr absjmp,
pc to L1 \ [A]@
ax di 0 d) mov,
ax ax 0 d) mov,
- AX pspush,
+ ax pspush,
ret,
xcode [A]@,
bx L1 i) mov, lblcallwr absjmp,
pc to L1 \ 8b [A]!
bx di 0 d) mov,
- AX pspop,
+ ax pspop,
bx 0 d) al mov,
ret,
pc 0 , EMETA_8B ,
bx L1 i) mov, lblcallwr absjmp,
pc to L1 \ 16b [A]!
bx di 0 d) mov,
- AX pspop,
+ ax pspop,
bx 0 d) 16b) ax mov,
ret,
pc nextmeta ! ( pc ) , EMETA_16B ,
bx L1 i) mov, lblcallwr absjmp,
pc to L1 \ [A]!
bx di 0 d) mov,
- AX pspop,
+ ax pspop,
bx 0 d) ax mov,
ret,
xcode [A]!,
@@ -952,7 +952,7 @@ xcode stack?
lblerrmsg absjmp,
pc to L2 \ find in sys dict
- lblcurword pspushN,
+ lblcurword i) pspush,
dx lblsysdict m) mov,
lblfind abscall,
[ebp]z?
@@ -965,7 +965,7 @@ pc to L1 \ execute imm word
xcode compword ( str -- )
wcall, parse
- AX pspop,
+ ax pspop,
ax ax test,
xwordlbl litn abs>rel jnz, \ literal: jump to litn
\ not a literal, find and compile
@@ -981,12 +981,12 @@ xcode runword ( str -- ) pc w>e lblsysdict pc>addr !
lblcompiling m) -1 i) test,
xwordlbl compword abs>rel jnz,
wcall, parse
- AX pspop,
+ ax pspop,
ax ax test,
xwordlbl noop abs>rel jnz, \ literal: nothing to do
\ not a literal, find and execute
L2 abscall,
- AX pspop,
+ ax pspop,
ax call,
xwordlbl stack? absjmp,
diff --git a/fs/xcomp/i386/pc/kernel.fs b/fs/xcomp/i386/pc/kernel.fs
@@ -23,17 +23,17 @@ pc to L4 \ segment with ffff limits
0 to realmode
xcode int13h ( drv head cyl sec dst -- )
- BX pspop,
- AX pspop, cl al mov, \ sec
- AX pspop, ch al mov, \ cyl
- AX pspop, dh al mov, \ head
- AX pspop, dl al mov, \ drive
+ bx pspop,
+ ax pspop, cl al mov, \ sec
+ ax pspop, ch al mov, \ cyl
+ ax pspop, dh al mov, \ head
+ ax pspop, dl al mov, \ drive
cli, $18 L4 jmpfar,
pc to L1 \ back to protected mode!
\ we still need to push di, bx and ax
dx $10 i) mov, ds dx mov, ss dx mov, es dx mov, gs dx mov, fs dx mov,
- BX pspush, AX pspush,
+ bx pspush, ax pspush,
lblidt m) lidt, sti,
\ restore PIC masks
ax pop, al $a1 i) out, al ah mov, al $21 i) out,
@@ -58,7 +58,7 @@ xcode int10h ( cx/dx bx ax -- bx ax )
\ save PIC masks and disable PIC for duration of int10h
al $21 i) in, ah al mov, al $a1 i) in, ax push,
al $ff i) mov, al $21 i) out, al $a1 i) out,
- AX pspop, BX pspop, CX pspop, cli, $18 L4 jmpfar,
+ ax pspop, bx pspop, cx pspop, cli, $18 L4 jmpfar,
\ To avoid lockups, we map all PIC IRQs on boot to words that acknowledge those
\ IRQs. The rest of PIC initialization is done in /drv/pc/pic.fs
