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/*
* 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 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
/* operand size switch. */
#define OPSIZE BYTE $0x66