Category : Files from Magazines
Archive   : PJ91.ZIP
Filename : TEST_BLK.ASM

title test block
include asm.inc
.stack

public main

BLOCK_SIZE equ 16384
TEST_SIZE equ 30 ; number of blocks to use in test

.data?
extrn argc:word,argv:dword

block_handles dw TEST_SIZE dup(?)

.const
ertx_block_data db 'Bad data in block',0


.code
extn startup,exit_program,perror,block_alloc,random,block_read,set_strerror
extn block_file_open,block_file_read


;; main
;
main proc
lea di,block_handles

mov cx,TEST_SIZE
mai1: call create_test_block
jc mai9
stosw
loop mai1

mov cx,TEST_SIZE*10 ; read random blocks
call read_random_blocks
jc mai9

cmp argc[bp],2
jb mai3 ; if no file name on command line

lds si,argv[bp] ; map file to virtual memory
mov si,[si+2]
call block_file_open
jc mai9 ; if file not found

mov cx,ax ; read file blocks in reverse order
mai2: mov ax,cx
dec ax
call block_file_read
jc mai9
loop mai2

mai3: mov cx,TEST_SIZE ; read more random blocks
call read_random_blocks
jc mai9

ret

mai9: mov si,NULL_POINTER
call perror
stc
ret
main endp


;; create test block
;
; exit AX,BX block handle
; Cf if error
;
create_test_block proc
pushm cx,di,es
call block_alloc
jc ctb1
mov cx,ax
shr cx,1
mov ax,bx
rep stosw
ctb1: popm es,di,cx
ret
create_test_block endp


;; read random blocks
;
; entry CX number of blocks to read
; exit Cf if error
; uses AX,CX,SI,DS
;
read_random_blocks proc
push bx
rrb1: mov ax,TEST_SIZE
call random
add ax,ax
mov si,ax
mov bx,block_handles[bp+si]
call block_read
jc rrb2
cmp bx,[si]
jne rrb3
loop rrb1
clc
rrb2: pop bx
ret

rrb3: lea ax,ertx_block_data ; *Bad data in block*
call set_strerror
jmp rrb2
read_random_blocks endp

end