Fujitsu MB91260B Series Hardware Manual page 470

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Specification of -K lib option when using character string operation function
When -K lib option is specified, the compiler performs inline expansion to some character string operation
functions. At this time, since the best processing method is selected, the processing may be changed to the
halfword or the word basis processing.
Therefore, processing to the little endian area is not executed correctly.
Please do not specify -K lib option when a process is executed to the little endian area by using the
character string operation function.
Also, please do not specify either -O4 option or -K speed option that including -K lib option.
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Use of double type and long double type
The access to the double type and the long double type is done by using a method of accessing to one high-
level word and one low-level word respectively. Therefore, accessing to the double type and the long
double type variables arranged in the little endian area yields an incorrect result.
The substitution of the variables of the same type allocated in the little endian area is possible. However,
these substitutions are occasionally replaced with the substitution of the constant as a result of optimization.
Please do not arrange either double type or long double type variables in the little endian area.
[Example of trouble] Transferring of double type data
double big = 1.0;
extern int little;
little = big;
The above-mentioned execution result is as follows:
(Big endian area)
3f f0 00 00 00 00
The result of transferring the double type data is incorrect.
(Correct result)
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Arrangement of stack in little endian area
When all or a part of the stack is arranged in the little endian area, operation is not guaranteed.
APPENDIX D Notes When Little Endian Area Is Used
/* Big endian area
/* Little endian area
/* Transferring of double type data */
→
00 00 00 00
00 00 00 00 00 00
*/
*/
(Little endian area)
f0 3f 00 00 00 00
f0 3f
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