4 * Copyright 2004 Develer S.r.l. (http://www.develer.com/)
5 * This file is part of DevLib - See devlib/README for information.
10 * \author Giovanni Bajo <rasky@develer.com>
12 * \brief DSP5680x task switching support
17 * Revision 1.2 2004/06/03 11:27:09 bernie
18 * Add dual-license information.
20 * Revision 1.1 2004/05/23 17:27:00 bernie
21 * Import kern/ subdirectory.
25 void asm_switch_context(void ** new_sp/*R2*/, void ** save_sp/*R3*/);
26 asm void asm_switch_context(void ** new_sp, void ** save_sp)
56 ; The compiler uses page 0 address locations X: 0x0030 - 0x003F as register
57 ; variables. Frequently accessed local variables are assigned to the page 0
58 ; registers instead of to stack locations so that load and store instructions
59 ; are shortened. Addresses X: 0x0030 - 0x0037 (page 0 registers MR0-MR7) are
60 ; volatile registers and can be overwritten. The remaining registers (page 0
61 ; registers MR8-MR15) are treated as non-volatile and, if used by a routine,
62 ; must be saved on entry and restored on exit.
64 ; So, register 0x30-0x37 are caller-save, while 0x38-0x3F are callee-save.
83 ; 28 words have been pushed on the stack.
108 ; restore hardware stack
110 move hws,la ; Clear HWS to ensure proper reload
116 ; restore all saved registers