ASM statement

Purpose

Identify an assembly-language statement.  PowerBASIC's Inline Assembler supports 8086/8088, 80286, 80386, 80486, Pentium, Floating-Point and MMX instructions.

Syntax

{! | ASM} opcode

Remarks

This statement allows you to place assembly-language code within your PowerBASIC source code.  An exclamation mark (!) serves as a shortcut for the ASM keyword.

Each group of ASM statements must preserve the following CPU registers if the assembler code causes them to change: ESI, EDI, ESP, EBP, and all segment registers.

No other statements may appear on the same line as an ASM statement; however, comments are acceptable.

! DB 1, 2, 3, 4, 5

! DD &H45001222, &HFFFF4327

Any variable referenced in an assembly-language statement must be defined prior to use.  For example:

x% = 10

! MOV AX, x%

You cannot access the target of a pointer with a single ASM statement as you might do in BASIC source code.  Instead, you must use the pointer address indirectly.  To simulate the BASIC statement INCR @x, you would write:

DIM x AS INTEGER PTR

ASM MOV EAX, x               ; EAX holds a pointer to

                             ; an Integer

ASM INC WORD PTR [EAX]       ; Add one to target value

String literals of up to four characters may be used in Inline Assembler code:
! MOV AL, "a"     ; move char a into reg AL

! MOV AX, "ab"       ; move chars ab into reg AX

!                    ; "a" into AL, "b" into AH

! MOV EAX, "abcd"    ; move chars abcd into reg EAX

PowerBASIC recognizes either an apostrophe ( ' ) or a semi-colon ( ; ) to specify a comment after a line of assembler code:

! PUSH EAX   ; save the EAX register

! PUSH EBX   ' save the EBX register

Restrictions

Care should be exercised to ensure registers are appropriately preserved when Inline Assembler code is intermixed with BASIC statements.  See Saving Registers for more information.

See also

The Inline Assembler

Example

To add the values a&, b&, and c&, you would write:

LOCAL a&, b&, c&, z&

! MOV  EAX, a&

! ADD  EAX, b&

! ADD  EAX, c&

! MOV  z&, EAX

Notes

The follow lists outline the supported mnemonics, data types, operators, and registers that can be used with the ASM statement.

AAA, AAD, AAM, AAS, ADC, ADD, AND

BOUND, BSF, BSR, BSWAP, BT, BTC, BTR, BTS

CALL, CBW, CCWD, CDQ, CLC, CLD, CLI, CMC, CMP, CMPSB, CMPSD, CMPSW, CMPXCHG, CPUID, CWDE

DAA, DAS, DEC, DIV

EMMS

F2XM1, FABS, FADD, FADDP, FCHS, FCLEX, FCOM, FCOMP, FCOMPP, FCOS, FDECSTP, FDIV, FDIVP, FDIVR, FDIVRP, FFREE, FIADD, FICOM, FICOMP, FIDIV, FIDIVR, FILD, FIMUL, FINCSTP, FINIT, FIST, FISTP, FISUB, FISUBR, FLD, FLD1, FLDCW, FLDENV, FLDL2E, FLDL2T, FLDLG2, FLDLN2, FLDPI, FLDZ, FMUL, FMULP, FNCLEX, FNINIT, FNLDCW, FNOP, FNSAVE, FNSTCW, FNSTENV, FNSTSW, FPATAN, FPREM, FPREM1, FPTAN, FRNDINT, FRSTOR, FSAVE, FSCALE, FSIN, FSINCOS, FSQRT, FST, FSTCW, FSTENV, FSTP, FSTSW, FSUB, FSUBP, FSUBR, FSUBRP, FTST, FUCOM, FUCOMP, FUCOMPP, FWAIT, FXAM, FXCH, FXTRACT, FYL2X, FYL2XP1

HLT

IDIV, IMUL, IN, INC, INSB, INSD, INSW, INT, INTO, IRET, IRETD

JA, JAE, JB, JBE, JC, JE, JECXZ, JG, JGE, JL, JLE, JMP, JNA, JNAE, JNB, JNBE, JNC, JNE, JNG, JNGE, JNL, JNLE, JNO, JNP, JNS, JNZ, JO, JP, JPE, JPO, JS, JZ

LAHF, LAR, LDS, LEA, LEAVE, LES, LFS, LGS, LOCK, LODSB, LODSD, LODSW, LOOP, LOOPE, LOOPNE, LOOPNZ, LOOPZ, LSL, LSS

MOV, MOVD, MOVQ, MOVSB, MOVSD, MOVSW, MOVSX, MOVZX, MUL

NEG, NOP, NOT

OR, OUT, OUTSB, OUTSD, OUTSW

PACKSSDW, PACKSSWB, PACKUSWB, PADDB, PADDD, PADDSB, PADDSW, PADDUSB, PADDUSW, PADDW, PAND, PANDN, PCMPEQB, PCMPEQD, PCMPEQW, PCMPGTB, PCMPGTD, PCMPGTW, PMADDWD, PMULHW, PMULLW, POP, POPA, POPAD, POPF, POPFD, POR, PSLLD, PSLLQ, PSLLW, PSRAD, PSRAW, PSRLD, PSRLQ, PSRLW, PSUBB, PSUBD, PSUBSB, PSUBSW, PSUBUSB, PSUBUSW, PSUBW, PUNPCKHBW, PUNPCKHDQ, PUNPCKHWD, PUNPCKLBW, PUNPCKLDQ, PUNPCKLWD, PUSH, PUSHA, PUSHAD, PUSHF, PUSHFD, PXOR

RCL, RCR, REP, REPE, REPNE, REPNZ, REPZ, RET, RETF, RETN, ROL, ROR

SAHF, SAL, SAR, SBB, SCASB, SCASD, SCASW, SETA, SETAE, SETB, SETBE, SETC, SETE, SETG, SETGE, SETL, SETLE, SETNA, SETNAE, SETNB, SETNBE, SETNC, SETNE, SETNG, SETNGE, SETNL, SETNLE, SETNO, SETNP, SETNS, SETNZ, SETO, SETP, SETPE, SETPO, SETS, SETZ, SHL, SHLD, SHR, SHRD, STC, STD, STI, STOSB, STOSD, STOSW, SUB

TEST

VERR, VERW

WAIT

XCHG, XLAT, XLATB, XOR

BYTE

DB, DD, DW, DWD, DWORD

FAR

NEAR

POINTER, PTR

QWD, QWORD

SHORT

TBY, TBYTE

WORD, WRD

Integer

Segments

CS, DS, ES, SS, FS, GS

MMX Registers

MM(0), MM(1), MM(2), MM(3), MM(4), MM(5), MM(6), MM(7)

MM0, MM1, MM2, MM3, MM4, MM5, MM6, MM7

Floating Point registers

ST(0), ST(1), ST(2), ST(3), ST(4), ST(5), ST(6), ST(7)