On Wed, 29 Jan 2020 00:11:40 -0500 George Koehler <kern...@gmail.com> wrote:
> You might have found a problem with mftb (move from time base) in > clang's assembler. Some of the other differences in your disassembly > might not cause problems. > > ... > - 4: 7f 8c 42 e6 mftb r28 > + 4: 7f 8c 42 a6 mfspr r28,268 This might not be a problem. 7f 8c 42 e6 is the old encoding, up to PowerPC 2.02. 7f 8c 42 a6 is the new encoding, from Power ISA 2.03. (PPC_Vers202_Book2_public.pdf, PowerISA_V2.03_Final_Public.pdf) 0x7f8c42e6 >> 1 & 0x3ff == 371 # old mftb 0x7f8c42a6 >> 1 & 0x3ff == 339 # new mfspr Power ISA 2.03 claims that the new mfspr works on most processors, but not in PowerPC 601 nor POWER3. It should work on processors supported by OpenBSD macppc. Later, I want to check if the new mfspr from clang really works on my iMac G3 (PowerPC 750). --George
