Class2
- 1. IBM PC Assembly Language and Programming by Peter AbelChapter 1: Basic Feature of PC hardwareMohammed Nazimuddin(나짐) Email:nazim@eslab.inha.ac.kr1210 Hi-tech centre.
- 2. Hardware FeaturesInternal HardwareProcessorMemoryRegisterExternal hardwareKeyboardMonitorDiskCD-ROM
- 3. Bits and BytesBits The fundamental building block of computer storage is Bit.A bit may beOff 0On 1
- 4. BytesA group of nine related bitsThe eight data bits provide the basis for binary arithmetic and characters256(28) – (00000000 ~ 11111111)One Bit parity.Rules of ParityMust be odd in each byte00001010 00001010(1)Represents a storage Location
- 6. Number systemBinaryBase 2 (0,1)Binary to Decimal01000001Bits are numbered from the right to left.b8b7b6b5b4b3b2b1b0Subscripts represent the place value, e.g. b6 has place value 26Conversion to decimal is done by evaluating the polynomialb8*28+ b7*27 + b6*26 + b5*25 +b4*24 +b3*23 +b2*22 +b1*21 + b0*20
- 7. In this case, 0+64+0+0+0+0+0+1 = 65DecimalBase 10( 0 to 9)Decimal to BinaryDivided by 2 Stop when 0Concatenate the Remainder is reverse orderExample65 100000165 / 2 = 32 r 132 / 2 = 16 r 016 / 2 = 8 r 08 / 2 = 4 r 04 / 2 = 2 r 02 / 2 = 1 r 01 / 2 = 0 r 1
- 8. HEXADECIMALBase 16(0 to 9, A..F)Hex to Binary
- 9. Expand each hex digit to the equivalent 4-bit binary form
- 10. You may omit leading zeros of leftmost digit
- 11. 37h = 0011 0111b
- 12. (or 110111b)
- 13. Binary to Hex
- 14. Group bits by fours (starting with least significant bits)
- 15. Add leading zeros as necessary to complete the last group
- 16. Convert each group to the equivalent hex digit
- 17. 0100 1110b = 4EhCharacter DataAmerican Standard Code for Information Interchange (ASCII)A 7-bit binary code for a set of 128 charactersUsually occupy a byte of storageLeading bit may be ignored or used differently by various programsA sequence of bytes containing ASCII codes is referred to as an ASCII string
- 18. Numeric DataBinary storagetwo’s complement, one’s complement, sign and magnitude, or biased representationsASCII storagesequence of ASCII bytes representing the digits of the number expressed in some radixBinary Coded Decimalsequence of nybbles representing digits 0-9 of the number
- 19. Binary StorageA pre-arranged storage size is usedtypically byte, word, doubleword, or quadwordRepresent a number in base two and encode the bits197d is 11000101bat least 8 bits will be required to store this number (leading zeros are added if necessary to fill additional bits for larger storage sizes)
- 20. Signed vs Unsigned CodesSigned Byte
- 21. two’s complement code is most common
- 22. only 7 bits are used for the magnitude
- 23. Minimum -128 is coded as 10000000b
- 24. Maximum +127 is coded as 01111111b
- 26. Unsigned Byte
- 27. all 8 bits used to represent the magnitude of the number
- 28. Minimum 0 (zero) is coded as 00000000b
- 29. Maximum 255 is coded as 11111111bStorage Sizes and RangesUnsigned IntegerByte
- 30. 0 to 255
- 31. Word
- 32. 0 to 65,535
- 33. Doubleword
- 35. Quadword
- 36. 0 to 18,446,744,073,709,551,615Signed (2’s Complement Code)Byte
- 37. -128 to 127
- 38. Word
- 40. Doubleword
- 42. Quadword
- 43. -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807Binary ArithmeticAdditionNumbers can be added in any number base
- 44. Use the same algorithm you practiced in second grade!
- 45. Binary Example: c ccc 10101+ 11111001000+0 = 00+1 = 11+0 = 11+1 = 101+1+1 = 11
- 46. Negative Binary NumberA negative binary value is expressed in Two’s complement notation. Two’s complementReverse the bitAdd 1Example: +65 Reverse bits Add 1 Number -65 0100000110111110 110111111
- 47. Subtraction How to Subtract 42 from 65 ? 65 : +(-43) : = 22
- 48. PC ComponentsSystem BoardProcessor, main memory, connectors, hard disk, etc… BusA bus with wires attached to the system board connects the components.Processor8088,8086,80286….PentiumExecution and Bus control unit
- 49. Execution and Bus control UnitEU: Execution UnitBIU: Bus interface UnitProgram controlInstruction Queue..
- 50. Intel 8086 OrganizationRegisters - storage locations found inside the processor for temporary storage of dataData Registers (16-bit)AX, BX, CX, DXAddress Registers (16-bit)Segment registers: CS, SS, DS, ESPointer registers: SP, BP, IPIndex registers: SI, DIStatus (Flags) register (16-bit)
- 51. Data RegistersThe data registers may be used for general purposes, however each has special usesAX : AccumulatorBX : BaseCX : CountDX : DataEach byte of the 4 data registers can be accessed independentlyAH, AL, BH, etc.These are referred to as 8-bit registers, but remember they are part of an existing register
- 52. Memory8086 - 1 megabyte of memory (220 bytes)Each byte is accessed by specifying an address (00000h through FFFFFh)20-bit addresses must be formed from 16-bits of information
- 53. Interrupt VectorsBIOS and DOS DataDOSApplication Program AreaVideoReservedBIOS
- 54. Segment Registers20-bit addresses are obtained by combining two 16-bit registers, segment:offsetAddress = segment*16(10h)+offsetExample CS: 010C IP: 14D2Address = 010C*10+14D2 = 010C0+14D2 Address = 02592Each segment is 64K, segments can start at any paragraph boundary
- 55. Program SegmentsDuring program execution, the segment registers are only changed if memory not currently accessible in an active segment must be accessedProgram bytes are arranged into distinct segments for convenienceCS -> segment containing machine instructionsSS -> segment containing storage for the stackDS -> segment containing data values and storageES -> segment for additional data or special memory operationsProgrammers must be aware of this organization
- 56. Instruction and Stack PointersIP contains the address of the next instruction to be executedIP specifies an offset into the CS segmentIP is not the operand of any instructionSP points to the top item on the stackSP is an offset into the SS segmentSP can be used as an operand in some instructions
- 57. BP and Index RegistersBP is a Base PointerSpecifies an offset into any segment, but most commonly the Stack segmentSI and DI are called Index registersThey normally specify an offset into the Data segment, although they can be used as offsets into any segmentSometimes they hold a number to be added to the address of an array (index)
- 58. FlagsIndividual bits are used to store the status of the microprocessorBits are set or cleared as the result of many operationsBits may be affected indirectly (by the execution of an instruction) or directly by an instruction designed to access the status word.