; -----------------------------------------------------------
; algorithm compares any two byte sequences CASE INSENSITIVE
; and returns zero if they are identical or the character
; count where the two byte sequences mismatch.
; -----------------------------------------------------------
push ebx
push esi
push edi
jmp @F
align 16
table:
db 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15
db 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31
db 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47
db 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63
db 64, 97, 98, 99,100,101,102,103,104,105,106,107,108,109,110,111
db 112,113,114,115,116,117,118,119,120,121,122, 91, 92, 93, 94, 95
db 96, 97, 98, 99,100,101,102,103,104,105,106,107,108,109,110,111
db 112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127
db 128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143
db 144,145,146,147,148,149,150,151,152,153,154,155,156,156,158,159
db 160,161,162,163,164,165,166,167,168,169,170,171,172,173,173,175
db 176,177,178,179,180,181,182,183,184,185,186,187,188,189,190,191
db 192,193,194,195,196,197,198,199,200,201,202,203,204,205,206,207
db 208,209,210,211,212,213,214,215,216,217,218,219,220,221,222,223
db 224,225,226,227,228,229,230,231,232,233,234,235,236,237,238,239
db 240,241,242,243,244,245,246,247,248,249,250,251,252,253,254,255
@@:
lea ebx, table ; table base address
mov esi, src ; 1st string in ESI
mov edi, dst ; 2nd string in EDI
mov ecx, ln ; length in ECX
add ecx, esi ; add ESI to get exit condition
@@:
mov al, [esi] ; get 1st byte
inc esi
xlatb ; replace it with byte in table
mov ah, al ; store it in AH
mov al, [edi] ; get 2nd byte
inc edi
xlatb ; replace it with byte in table
cmp ah, al ; compare if equal
jne @F ; jump out if not equal
cmp esi, ecx ; exit on length
jl @B
@@:
sub esi, src
.if esi == ln
xor eax, eax
.else
mov eax, esi
.endif