Capitals

[Vb Programmer]

how would i change this string 'Hello World' all into capitals 'HELLO WORLD'
in sim8086

[PASSERTHRU]

A-Z ... 41h - 5Ah ... 0100_0001b - 0101_1010b
a-z ... 61h - 7Ah .... 0110_0001b - 0111_1010b

bit 0-7 are the same except bit 5 (set for lower clear for upper)

what you want to do is :

lea si,ascii
mov di,si
cld ; clear direction flag (just for bullet proofing)
toupper:lodsb ; load upper or lower charictor
and al,0DFh ; mask out bit 5
stosb ; store upper
or al,al ; test for zero terminator
jnz toupper ; loop until zero is reached