Usage Restrictions Concerning Big Endian Format With Nec Development Tools; Word Data Little Endian Format Example; Word Data Big Endian Format Example - Renesas NU85E Preliminary User's Manual

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4.6.2 Usage restrictions concerning big endian format with NEC development tools

(1) When using the debugger (ID850)
Only the memory window display supports the big endian format.
(2) When using the compiler (CA850)
(a) C language restrictions
(i) The following restrictions are attached to variables configured in a big endian space.
<1> unions cannot be used.
<2> bitfields cannot be used.
<3> Accesses based on the cast (changed access size) cannot be used.
<4> Variables with initial values cannot be used.
(ii) Because the access size may change due to optimization, it is necessary to specify the following
optimization suppression options.
• For global optimization sections (opt850)..................-Wo, -XTb
• For model-based optimization sections (impr850).....-Wi, +arg_reg_opt=OFF, +stld_trans_opt=OFF
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CHAPTER 4 BCU
Figure 4-9. Word Data Little Endian Format Example
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Figure 4-10. Word Data Big Endian Format Example
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