Blargg made a GB-Z80 testing program: http://h1.ripway.com/blargg/temp/gb_cpu_test.zip
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Among the instructions that fail are:
E8: ADD SP,nn
F8: LD HL,SP+nn
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Those instructions are quite deceptive with what they do to flags: They use the lower byte of SP added to the unsigned byte to determine halfcarry and carry flags. All other flags are cleared.
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Several other tests also fail.