ref: dc593372bfc4224c6cf91d2031d0ad0aeadaddfe
dir: /sys/src/boot/pc/x16.h/
/* * Can't write 16-bit code for 8a without getting into * lots of bother, so define some simple commands and * output the code directly. * * N.B. CALL16(x) kills DI, so don't expect it to be * saved across calls. */ #define rAX 0 /* rX */ #define rCX 1 #define rDX 2 #define rBX 3 #define rSP 4 /* SP */ #define rBP 5 /* BP */ #define rSI 6 /* SI */ #define rDI 7 /* DI */ #define rAL 0 /* rL */ #define rCL 1 #define rDL 2 #define rBL 3 #define rAH 4 /* rH */ #define rCH 5 #define rDH 6 #define rBH 7 #define rES 0 /* rS */ #define rCS 1 #define rSS 2 #define rDS 3 #define rFS 4 #define rGS 5 #define xSI 4 /* rI (index) */ #define xDI 5 #define xBP 6 #define xBX 7 #define rCR0 0 /* rC */ #define rCR2 2 #define rCR3 3 #define rCR4 4 #define OP(o, m, ro, rm) BYTE $o; /* op + modr/m byte */ \ BYTE $(((m)<<6)|((ro)<<3)|(rm)) #define OPrm(o, r, m) OP(o, 0x00, r, 0x06); /* general r <-> m */ \ WORD $m; #define OPrr(o, r0, r1) OP(o, 0x03, r0, r1); /* general r -> r */ #define LW(m, rX) OPrm(0x8B, rX, m) /* m -> rX */ #define LXW(x, rI, r) OP(0x8B, 0x02, r, rI); /* x(rI) -> r */ \ WORD $x #define LBPW(x, r) OP(0x8B, 0x02, r, xBP); /* x(rBP) -> r */ \ WORD $x #define LB(m, rB) OPrm(0x8A, rB, m) /* m -> r[HL] */ #define LXB(x, rI, r) OP(0x8A, 0x01, r, rI); /* x(rI) -> r */ \ BYTE $x #define LBPB(x, r) OP(0x8A, 0x01, r, xBP); /* x(rBP) -> r */ \ BYTE $x #define SW(rX, m) OPrm(0x89, rX, m) /* rX -> m */ #define SXW(r, x, rI) OP(0x89, 0x02, r, rI); /* r -> x(rI) */ \ WORD $x #define SBPW(r, x) OP(0x89, 0x02, r, xBP); /* r -> x(rBP) */ \ WORD $(x) #define SBPWI(i, x) OP(0xC7, 0x01, 0, xBP); /* i -> x(rBP) */ \ BYTE $(x); WORD $(i) #define STB(rB, m) OPrm(0x88, rB, m) /* rB -> m */ #define SXB(r, x, rI) OP(0x88, 0x01, r, rI); /* rB -> x(rI) */ \ BYTE $x #define SBPB(r, x) OP(0x88, 0x01, r, xBP); /* r -> x(rBP) */ \ BYTE $x #define SBPBI(i, x) OP(0xC6, 0x01, 0, xBP); /* i -> x(rBP) */ \ BYTE $(x); BYTE $(i) #define LWI(i, rX) BYTE $(0xB8+rX); /* i -> rX */ \ WORD $i; #define LBI(i, rB) BYTE $(0xB0+rB); /* i -> r[HL] */ \ BYTE $i #define MW(r0, r1) OPrr(0x89, r0, r1) /* r0 -> r1 */ #define MFSR(rS, rX) OPrr(0x8C, rS, rX) /* rS -> rX */ #define MTSR(rX, rS) OPrr(0x8E, rS, rX) /* rX -> rS */ #define MFCR(rC, rX) BYTE $0x0F; /* rC -> rX */ \ OP(0x20, 0x03, rC, rX) #define MTCR(rX, rC) BYTE $0x0F; /* rX -> rC */ \ OP(0x22, 0x03, rC, rX) #define ADC(r0, r1) OPrr(0x11, r0, r1) /* r0 + r1 -> r1 */ #define ADD(r0, r1) OPrr(0x01, r0, r1) /* r0 + r1 -> r1 */ #define ADDI(i, r) OP(0x81, 0x03, 0x00, r);/* i+r -> r */ \ WORD $i; #define AND(r0, r1) OPrr(0x21, r0, r1) /* r0&r1 -> r1 */ #define ANDI(i, r) OP(0x81, 0x03, 0x04, r);/* i&r -> r */ \ WORD $i; #define CLR(r) OPrr(0x31, r, r) /* r^r -> r */ #define CLRB(r) OPrr(0x30, r, r) /* r^r -> r */ #define CMP(r0, r1) OPrr(0x39, r0, r1) /* r1-r0 -> flags */ #define CMPI(i, r) OP(0x81, 0x03, 0x07, r);/* r-i -> flags */ \ WORD $i; #define CMPBR(r0, r1) OPrr(0x38, r0, r1) /* r1-r0 -> flags */ #define DEC(r) BYTE $(0x48|r) /* r-1 -> r */ #define DIV(r) OPrr(0xF7, 0x06, r) /* rDX:rAX/r -> rAX, rDX:rAX%r -> rDX */ #define INC(r) BYTE $(0x40|r) /* r+1 -> r */ #define MUL(r) OPrr(0xF7, 0x04, r) /* r*rAX -> rDX:rAX */ #define IMUL(r0, r1) BYTE $0x0F; /* r0*r1 -> r1 */ \ OPrr(0xAF, r1, r0) /* (signed) */ #define OR(r0, r1) OPrr(0x09, r0, r1) /* r0|r1 -> r1 */ #define ORB(r0, r1) OPrr(0x08, r0, r1) /* r0|r1 -> r1 */ #define ORI(i, r) OP(0x81, 0x03, 0x01, r);/* i|r -> r */ \ WORD $i; #define ROLI(i, r) OPrr(0xC1, 0x00, r); /* r<<>>i -> r */ \ BYTE $i; #define SHLI(i, r) OPrr(0xC1, 0x04, r); /* r<<i -> r */ \ BYTE $i; #define SHLBI(i, r) OPrr(0xC0, 0x04, r); /* r<<i -> r */ \ BYTE $i; #define SHRI(i, r) OPrr(0xC1, 0x05, r); /* r>>i -> r */ \ BYTE $i; #define SHRBI(i, r) OPrr(0xC0, 0x05, r); /* r>>i -> r */ \ BYTE $i; #define SBB(r0, r1) OPrr(0x19, r0, r1) /* r1-r0 -> r1 */ #define SUB(r0, r1) OPrr(0x29, r0, r1) /* r1-r0 -> r1 */ #define SUBI(i, r) OP(0x81, 0x03, 0x05, r);/* r-i -> r */ \ WORD $i; #define STOSW STOSL #define CALL16(f) LWI(f, rDI); /* &f -> rDI */ \ BYTE $0xFF; /* (*rDI) */ \ BYTE $0xD7; #define FARJUMP16(s, o) BYTE $0xEA; /* jump to ptr16:16 */ \ WORD $o; WORD $s #define FARJUMP32(s, o) BYTE $0x66; /* jump to ptr32:16 */ \ BYTE $0xEA; LONG $o; WORD $s #define DELAY BYTE $0xEB; /* jmp .+2 */ \ BYTE $0x00 #define BIOSCALL(b) INT $b /* INT $b */ #define PEEKW BYTE $0x26; /* MOVW rES:[rBX], rAX */ \ BYTE $0x8B; BYTE $0x07 #define POKEW BYTE $0x26; /* MOVW rAX, rES:[rBX] */ \ BYTE $0x89; BYTE $0x07 #define OUTPORTB(p, d) LBI(d, rAL); /* d -> I/O port p */ \ BYTE $0xE6; \ BYTE $p; DELAY #define PUSHA BYTE $0x60 #define PUSHR(r) BYTE $(0x50|r) /* r -> (--rSP) */ #define PUSHS(rS) BYTE $(0x06|((rS)<<3)) /* rS -> (--rSP) */ #define PUSHI(i) BYTE $0x68; WORD $i; /* i -> --(rSP) */ #define POPA BYTE $0x61 #define POPR(r) BYTE $(0x58|r) /* (rSP++) -> r */ #define POPS(rS) BYTE $(0x07|((rS)<<3)) /* (rSP++) -> r */ #define NOP BYTE $0x90 /* nop */ #define LGDT(gdtptr) BYTE $0x0F; /* LGDT */ \ BYTE $0x01; BYTE $0x16; \ WORD $gdtptr #define LIDT(idtptr) BYTE $0x0F; /* LIDT */ \ BYTE $0x01; BYTE $0x1e; \ WORD $idtptr /* operand size switch. */ #define OPSIZE BYTE $0x66 #define ADSIZE BYTE $0x67