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These + and - characters in a branch mnemonic can cause the assembler to produce conditional branch instructions with that hint the branch predictor. The default for forward branches is -, and for backward branches is +. If a mnemonic is issued with the opposite sign, then bit 10 of the instruction (the LSB of the BO field) is set. My long-retired "ppcdisasm" script inserted these hints unconditionally, despite 98% of them not being required. The code is much cleaner now. I read in some old MPW release notes that PPCAsm and PPCLink together exhibit a quirk when linking conditional branches to imported symbols. PPCAsm always assembles these conditional branches as if they were forward branches (that is, a + hint will always set the hint bit, and a - hint will never). I hoped to use this property to divine whether the NanoKernel was linked from one or many assembly files, but I was frustrated by the lack of conditional branches between files. |
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| .. | ||
| InnerMakeFile | ||
| MakeFile | ||
| NanoKernel.s | ||
| NKAdditions.s | ||
| NKAddressSpaceMPCalls.s | ||
| NKBuiltinInit.s | ||
| NKCache.s | ||
| NKConsoleLog.s | ||
| NKEquates.s | ||
| NKIndex.s | ||
| NKInit.s | ||
| NKInterrupts.s | ||
| NKMacros.s | ||
| NKMPCalls.s | ||
| NKPaging.s | ||
| NKPoolAllocator.s | ||
| NKPowerCalls.s | ||
| NKPrimaryIntHandlers.s | ||
| NKProcFlagsTbl.s | ||
| NKProcInfoTbl.s | ||
| NKReplacementInit.s | ||
| NKRTASCalls.s | ||
| NKScheduler.s | ||
| NKScreenConsole.s | ||
| NKSleep.s | ||
| NKSync.s | ||
| NKTasks.s | ||
| NKThud.s | ||
| NKTimers.s | ||
| NKTranslation.s | ||
| NKVMCalls.s | ||