Macintosh-SW
/
NetBoot
mirror of https://github.com/elliotnunn/NetBoot.git
1
0
Fork 0
Code Issues Projects Releases Wiki Activity

Init performance fix 

Quite an embarrassing one. I search the stack for a known 4-byte value.
This search starts at the stack pointer and continues towards low
memory. Oops! I was searching nearly the entire address space.
This commit is contained in:
Elliot Nunn 2021-03-02 19:11:57 +08:00
parent a96d61eca7
commit c5947f2652
1 changed files with 2 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
ChainLoader.a
View File

@ -56,8 +56,8 @@ ResumeAfterCopy
; We do this by scanning the stack for the return address of the original _Read.
move.l $2AE,A0 ; A0 = ROMBase (lower limit)
lea $4000(A0),A1 ; A1 = ROMBase + a bit (upper limit)
lea -2(SP),A2
.loop subq.l #2,A2 ; A2 = where we search the stack
move.l SP,A2
.loop addq.l #2,A2 ; A2 = where we search the stack
move.l (A2),A3 ; A3 = potential return address
cmp.l A0,A3 ; lower limit check
bls.s .loop