# lecture3 - CIS 450 Computer Architecture and Organization...

This preview shows pages 1–7. Sign up to view the full content.

CIS 450 Computer Architecture and Organization Lecture 3: Integer Representation Mitch Neilsen Mitch Neilsen [email protected] [email protected] 219D Nichols Hall 219D Nichols Hall

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
–2– Encoding Integers Encoding Integers z Sign + Magnitude Form Sign + Magnitude Form ± Complex arithmetic operations ± Two representations for 0, +0 and -0 z One One ’s Complement Form s Complement Form ± Compute negative value by complementing x: -x = ~x ± Simple arithmetic operations ± Still two representations for 0, +0 and -0 z Two Two ’s Complement Form s Complement Form ± Compute negative value by complementing and adding one: -x = ~x + 1 ± One representation for 0 ± More negative values than positive values (by one)
–3– Encoding Integers Encoding Integers short int x = 15213; short int y = -15213; ± C short 2 bytes long Sign Bit Sign Bit ± For 2’s complement, most significant bit indicates sign z 0 for nonnegative z 1 for negative B 2 T ( X ) =− x w 1 2 w 1 + x i 2 i i = 0 w 2 B 2 U ( X ) = x i 2 i i = 0 w 1 Unsigned Two’s Complement Sign Bit Decimal Hex Binary x 15213 3B 6D 00111011 01101101 y -15213 C4 93 11000100 10010011

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
–4– Encoding Example (Cont.) Encoding Example (Cont.) x = 15213: 00111011 01101101 y = -15213: 11000100 10010011 Weight 15213 -15213 1 1 1 1 1 2 0 0 1 2 4 1 4 0 0 8 1 8 0 0 16 0 0 1 16 32 1 32 0 0 64 1 64 0 0 128 0 0 1 128 256 1 256 0 0 512 1 512 0 0 1024 0 0 1 1024 2048 1 2048 0 0 4096 1 4096 0 0 8192 1 8192 0 0 16384 0 0 1 16384 -32768 0 0 1 -32768 Sum 15213 -15213
–5– Numeric Ranges Numeric Ranges Unsigned Values Unsigned Values ± UMin =0 000…0 ± UMax = 2 w –1 111…1 Two Two ’s Complement Values s Complement Values ± TMin =– 2 w –1 100…0 ± TMax = 2 w –1 011…1 Other Values Other Values ± Minus 1 111…1 Decimal Hex Binary UMax 65535 FF FF 11111111 11111111 TMax 32767 7F FF 01111111 11111111 TMin -32768 80 00 10000000 00000000 -1 -1 FF FF 11111111 11111111 0 0 00 00 00000000 00000000 Values for W = 16

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
–6– Values for Different Word Sizes Observations Observations ± | TMin | = TMax + 1 z Asymmetric range ± UMax =2 * TMax + 1 C Programming C Programming ± #include <limits.h> z K&R App. B11 ± Declares constants, e.g.,
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### Page1 / 21

lecture3 - CIS 450 Computer Architecture and Organization...

This preview shows document pages 1 - 7. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online