25 lines
768 B
C
25 lines
768 B
C
#ifndef __ASM_CASIO_TRAPA_H__
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# define __ASM_CASIO_TRAPA_H__
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/*
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** Normally the SH3/SH4 processor provide a "trapa" instruction which allow
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** tipping between userland and kernel. But Casio's don't use this method
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** (this is why we are always in "privilegied mode" and we can do whatever
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** we whant) but use custom calling convention to access the syscall call.
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**
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** The convention whant that the user jump into the syscall trampoline code
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** located at 0x80010070 for fx9860g and 0x80020070 for fxcg20/50.
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*/
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#ifdef __SUPPORT_CASIO_ABI_FXCG50
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# define casio_trapa(id) \
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mov.l syscall_table, r2 ;\
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mov.l syscall_id, r0 ;\
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jmp @r2 ;\
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nop ;\
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.align 4 ;\
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syscall_table: .long 0x80020070 ;\
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syscall_id: .long id
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#endif
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#endif /*__ASM__CASIO_TRAPA_H__*/
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