9bootfat: rename Extend to File as fat files are not really extends anymore :)

[plan9front.git] / sys / src / boot / pc / l.s

diff --git a/sys/src/boot/pc/l.s b/sys/src/boot/pc/l.s
index ecc9d9e57e250fc12ad9355d5633961537dc369e..e8fa45954c2bb396d7c9d67bc8aa37a0ca07b97d 100644 (file)
--- a/sys/src/boot/pc/l.s
+++ b/sys/src/boot/pc/l.s
@@ -5,7 +5,9 @@
 
 #define DATA32SEL SELECTOR(1, SELGDT, 0)
 #define EXEC32SEL SELECTOR(2, SELGDT, 0)
-#define EXEC16SEL SELECTOR(3, SELGDT, 0)
+#define DATA16SEL SELECTOR(3, SELGDT, 0)
+#define EXEC16SEL SELECTOR(4, SELGDT, 0)
+
 #define SEGSS BYTE $0x36
 #define SEGES BYTE $0x26
 #define FARRET BYTE $0xCB
@@ -21,33 +23,77 @@ TEXT origin(SB), $0
        PUSHI(start(SB))
 
 TEXT pmode32(SB), $0
+       CLI
+
+       /* disable nmi */
+       PUSHA
+       LWI(0x70, rDX)
+       INB
+       ANDB $0x7F, AL
+       OUTB
+       POPA
+
+       /* get return pc */
        POPR(rDI)
+
+       /* make sure stack is at 0000: */
+       CLR(rCX)
+       MTSR(rCX, rSS)
+       OPSIZE; ANDL $0xFFFF, SP
+
+       /* convert 16-bit return pc to far pointer */
+       PUSHI(EXEC32SEL)
+       PUSHR(rDI)
+
+       /* load gdt */
        SEGSS; LGDT(tgdtptr(SB))
+
+       /* enable protected mode */
        MFCR(rCR0, rCX)
        ORB $1, CL
        MTCR(rCX, rCR0)
-       PUSHI(EXEC32SEL)
-       PUSHR(rDI)
+
+       /* flush */
+       FARJUMP16(EXEC16SEL, pmode32flush(SB));
+TEXT pmode32flush(SB), $0
+
+       /* load 32-bit protected mode data selector */
        LWI(DATA32SEL, rCX)
+
 _segret:
+       /* load all data segments */
        MTSR(rCX, rDS)
        MTSR(rCX, rES)
+       MTSR(rCX, rFS)
+       MTSR(rCX, rGS)
        MTSR(rCX, rSS)
        FARRET
 
 TEXT rmode16(SB), $0
-       POPL DI
-       OPSIZE; BYTE $0xEA
-       WORD $unreal(SB)
-       WORD $EXEC16SEL
+       /* setup farret to rmode16x */
+       PUSHL $EXEC16SEL
+       PUSHL $rmode16x(SB)
+
+       /* load 16-bit protected mode data selector */
+       MOVL $DATA16SEL, CX
+       JMP _segret
 
-TEXT unreal(SB), $0
+TEXT rmode16x(SB), $0
+       /* disable protected mode */
        MFCR(rCR0, rCX)
        ANDB $0xfe, CL
        MTCR(rCX, rCR0)
+
+       /* flush */
+       FARJUMP16(0, rmode16flush(SB));
+TEXT rmode16flush(SB), $0
+
+       /*
+        * load 16-bit realmode data segment 0000: and
+        * return to 32 bit return pc interpreted
+        * as 16 bit far pointer.
+        */
        CLR(rCX)
-       PUSHR(rCX)
-       PUSHR(rDI)
        JMP _segret
 
 TEXT tgdt(SB), $0 
@@ -63,12 +109,16 @@ TEXT tgdt(SB), $0
        LONG $(0xFFFF)
        LONG $(SEGG|SEGD|(0xF<<16)|SEGP|SEGPL(0)|SEGEXEC|SEGR)
 
-       /* exec segment descriptor for 4 gigabytes (PL 0) 16-bit */
+       /* data segment descriptor for (PL 0) 16-bit */
+       LONG $(0xFFFF)
+       LONG $((0xF<<16)|SEGP|SEGPL(0)|SEGDATA|SEGW)
+
+       /* exec segment descriptor for (PL 0) 16-bit */
        LONG $(0xFFFF)
-       LONG $(SEGG|(0xF<<16)|SEGP|SEGPL(0)|SEGEXEC|SEGR)
+       LONG $((0xF<<16)|SEGP|SEGPL(0)|SEGEXEC|SEGR)
 
 TEXT tgdtptr(SB), $0 
-         WORD $(4*8) 
+         WORD $(5*8) 
          LONG $tgdt(SB)
 
 TEXT jump(SB), $0
@@ -79,20 +129,31 @@ TEXT halt(SB), $0
 _halt:
        JMP _halt
 
+TEXT spllo(SB), $0
+       /* enable nmi */
+       PUSHA
+       LWI(0x70, rDX)
+       INB
+       ORB $0x80, AL
+       OUTB
+       POPA
+
+       STI
+       RET
+
 TEXT getc(SB), $0
        CALL rmode16(SB)
-       STI
+       CALL16(spllo(SB))
        MOVB $0x00, AH
        BIOSCALL(0x16)
 _getcret:
-       CLI
        CALL16(pmode32(SB))
        ANDL $0xFF, AX
        RET
 
 TEXT gotc(SB), $0
        CALL rmode16(SB)
-       STI
+       CALL16(spllo(SB))
        MOVB $0x01, AH
        BIOSCALL(0x16)
        JNZ _getcret
@@ -102,17 +163,43 @@ TEXT gotc(SB), $0
 TEXT putc(SB), $0
        MOVL 4(SP),AX
        CALL rmode16(SB)
-       STI
+       CALL16(spllo(SB))
        MOVB $0x0E, AH
        BIOSCALL(0x10)
 _pret32:
-       CLI
        CALL16(pmode32(SB))
        ANDL $0xFFFF, AX
        RET
 
 #ifdef PXE
 
+TEXT pxeinit(SB), $0
+       CALL rmode16(SB)
+
+       /* get pxe env structure in ES:BX */
+       LWI(0x5650, rAX)
+       BIOSCALL(0x1A)
+       JC _pret32
+
+       /* !PXE or PXEENV+ signature */
+       SEGES; LXW(0, xBX, rAX)
+       CMPI((('!'<<0)|('P'<<8)), rAX)
+       JEQ _getentry
+       CMPI((('P'<<0)|('X'<<8)), rAX)
+       JNE _pret32
+
+       SEGES; LXW(0x2A, xBX, rAX)
+       SEGES; LXW(0x28, xBX, rBX)
+       MTSR(rAX, rES)
+
+_getentry:
+       SEGES; LXW(0x12, xBX, rAX)
+       SW(rAX, pxepseg(SB))
+       SEGES; LXW(0x10, xBX, rAX)
+       SW(rAX, pxepoff(SB))
+       CLR(rAX)
+       JMP _pret32
+
 TEXT pxecallret(SB), $0
        ADDI(6, rSP)
        JMP _pret32
@@ -121,7 +208,6 @@ TEXT pxecall(SB), $0
        MOVL op+4(SP),AX
        MOVL buf+8(SP),SI
        CALL rmode16(SB)
-       CLI
 
        CLR(rCX)
        PUSHR(rCX)
@@ -130,47 +216,29 @@ TEXT pxecall(SB), $0
        /* opcode */
        PUSHR(rAX)
 
+       /* farcall */
        PUSHR(rCX)
        PUSHI(pxecallret(SB))
 
-       /* get pxe env structure in ES:BX */
-       LWI(0x5650, rAX)
-       BIOSCALL(0x1A)
-       JC _farret
-
-       /* !PXE or PXEENV+ signature */
-       SEGES; LXW(0, xBX, rAX)
-       CMPI((('!'<<0)|('P'<<8)), rAX)
-       JEQ _getentry
-       CMPI((('P'<<0)|('X'<<8)), rAX)
-       JNE _farret
-
-       SEGES; LXW(0x2A, xBX, rAX)
-       SEGES; LXW(0x28, xBX, rBX)
-       MTSR(rAX, rES)
-
-_getentry:
-       SEGES; LXW(0x12, xBX, rAX)
+       LW(pxepseg(SB), rAX)
        PUSHR(rAX)
-       SEGES; LXW(0x10, xBX, rAX)
+       LW(pxepoff(SB), rAX)
        PUSHR(rAX)
 
-_pxecall:
+       CALL16(spllo(SB))
+
        CLR(rAX)
        CLR(rBX)
        CLR(rCX)
        CLR(rDX)
        CLR(rDI)
        CLR(rSI)
-_farret:
        FARRET
 
-_pxeplus:
-       CMPI((('P'<<0)|('X'<<8)), rAX)
-       JNE _farret
-
-       PUSHR(rAX)
-       JMP _pxecall
+TEXT pxepseg(SB), $0
+       WORD $0
+TEXT pxepoff(SB), $0
+       WORD $0
 
 #else /* PXE */
 
@@ -218,9 +286,8 @@ TEXT readsect(SB), $0
        MOVW 10(SP), BX
        MOVL 12(SP), SI 
        CALL rmode16(SB)
-       STI
+       CALL16(spllo(SB))
        CALL16(readsect16(SB))
-       CLI
        CALL16(pmode32(SB))
        ANDL $0xFFFF, AX
        RET