如果能标个注释的话就太谢谢了，还会额外加分
tick equ 10000
t100us equ 256-50
c100us equ 30h
ledbuf equ 0
led equ 40h
ljmp start
org 000bh
t0int:
push psw
mov a,c100us+1
jnz goon
dec c100us
goon:
dec c100us+1
mov a,c100us
orl a,c100us+1
jnz exit
mov c100us,#high(tick)
mov c100us+1,#low(tick)
cpl ledbuf
exit:
pop psw
reti
start:
mov tmod,#02h
mov th0,#t100us
mov tl0,#t100us
mov ie,#10000010b
setb tr0
clr ledbuf
clr led
mov c100us,#high(tick)
mov c100us+1,#low(tick)
loop:
mov c,ledbuf
mov led,c
ljmp loop
end