Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   1) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   2) MOTOROLA MICROPROCESSOR & MEMORY TECHNOLOGY GROUP
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   3) M68000 Hi-Performance Microprocessor Division
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   4) M68060 Software Package
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   5) Production Release P1.00 -- October 10, 1994
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   6) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   7) M68060 Software Package Copyright © 1993, 1994 Motorola Inc.  All rights reserved.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   8) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   9) THE SOFTWARE is provided on an "AS IS" basis and without warranty.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  10) To the maximum extent permitted by applicable law,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  11) MOTOROLA DISCLAIMS ALL WARRANTIES WHETHER EXPRESS OR IMPLIED,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  12) INCLUDING IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  13) and any warranty against infringement with regard to the SOFTWARE
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  14) (INCLUDING ANY MODIFIED VERSIONS THEREOF) and any accompanying written materials.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  15) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  16) To the maximum extent permitted by applicable law,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  17) IN NO EVENT SHALL MOTOROLA BE LIABLE FOR ANY DAMAGES WHATSOEVER
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  18) (INCLUDING WITHOUT LIMITATION, DAMAGES FOR LOSS OF BUSINESS PROFITS,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  19) BUSINESS INTERRUPTION, LOSS OF BUSINESS INFORMATION, OR OTHER PECUNIARY LOSS)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  20) ARISING OF THE USE OR INABILITY TO USE THE SOFTWARE.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  21) Motorola assumes no responsibility for the maintenance and support of the SOFTWARE.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  22) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  23) You are hereby granted a copyright license to use, modify, and distribute the SOFTWARE
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  24) so long as this entire notice is retained without alteration in any modified and/or
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  25) redistributed versions, and that such modified versions are clearly identified as such.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  26) No licenses are granted by implication, estoppel or otherwise under any patents
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  27) or trademarks of Motorola, Inc.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  28) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  29) 68060 INTEGER SOFTWARE PACKAGE (Kernel version)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  30) ------------------------------------------------
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  31) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  32) The file isp.sa contains the 68060 Integer Software Package.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  33) This package is essentially an exception handler that can be
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  34) integrated into an operating system to handle the "Unimplemented
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  35) Integer Instruction" exception vector #61.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  36) This exception is taken when any of the integer instructions
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  37) not hardware implemented on the 68060 are encountered. The
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  38) isp.sa provides full emulation support for these instructions.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  39) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  40) The unimplemented integer instructions are:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  41) 	64-bit divide
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  42) 	64-bit multiply
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  43) 	movep
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  44) 	cmp2
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  45) 	chk2
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  46) 	cas (w/ a misaligned effective address)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  47) 	cas2
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  48) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  49) Release file format:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  50) --------------------
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  51) The file isp.sa is essentially a hexadecimal image of the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  52) release package. This is the ONLY format which will be supported.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  53) The hex image was created by assembling the source code and
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  54) then converting the resulting binary output image into an
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  55) ASCII text file. The hexadecimal numbers are listed
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  56) using the Motorola Assembly Syntax assembler directive "dc.l"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  57) (define constant longword). The file can be converted to other
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  58) assembly syntaxes by using any word processor with a global
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  59) search and replace function.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  60) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  61) To assist in assembling and linking this module with other modules,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  62) the installer should add a symbolic label to the top of the file.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  63) This will allow calling routines to access the entry points
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  64) of this package.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  65) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  66) The source code isp.s has also been included but only for
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  67) documentation purposes.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  68) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  69) Release file structure:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  70) -----------------------
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  71) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  72) (top of module)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  73) 	-----------------
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  74) 	|		| - 128 byte-sized section
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  75)    (1)  |   Call-Out    | - 4 bytes per entry (user fills these in)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  76) 	|		| - example routines in iskeleton.s
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  77) 	-----------------
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  78) 	|		| - 8 bytes per entry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  79)    (2)  | Entry Point   | - user does a "bra" or "jmp" to this address
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  80) 	|               |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  81) 	-----------------
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  82) 	|		| - code section
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  83)    (3)  ~		~
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  84) 	|		|
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  85) 	-----------------
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  86) (bottom of module)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  87) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  88) The first section of this module is the "Call-out" section. This section
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  89) is NOT INCLUDED in isp.sa (an example "Call-out" section is provided at
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  90) the end of the file iskeleton.s). The purpose of this section is to allow
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  91) the ISP routines to reference external functions that must be provided
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  92) by the host operating system. This section MUST be exactly 128 bytes in
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  93) size. There are 32 fields, each 4 bytes in size. Each field corresponds
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  94) to a function required by the ISP (these functions and their location are
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  95) listed in "68060ISP call-outs" below). Each field entry should contain
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  96) the address of the corresponding function RELATIVE to the starting address
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  97) of the "call-out" section. The "Call-out" section must sit adjacent to the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  98) isp.sa image in memory.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  99) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) The second section, the "Entry-point" section, is used by external routines
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) to access the functions within the ISP. Since the isp.sa hex file contains
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) no symbol names, this section contains function entry points that are fixed
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) with respect to the top of the package. The currently defined entry-points
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) are listed in section "68060 ISP entry points" below. A calling routine
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) would simply execute a "bra" or "jmp" that jumped to the selected function
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) entry-point.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) For example, if the 68060 hardware took a "Unimplemented Integer Instruction"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) exception (vector #61), the operating system should execute something
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) similar to:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) 	bra	_060ISP_TOP+128+0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) (_060ISP_TOP is the starting address of the "Call-out" section; the "Call-out"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) section is 128 bytes long; and the Unimplemented Integer ISP handler entry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) point is located 0 bytes from the top of the "Entry-point" section.)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) The third section is the code section. After entering through an "Entry-point",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) the entry code jumps to the appropriate emulation code within the code section.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) 68060ISP call-outs: (details in iskeleton.s)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) --------------------
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) 0x000:	_060_real_chk
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) 0x004:	_060_real_divbyzero
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) 0x008:	_060_real_trace
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) 0x00c:	_060_real_access
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) 0x010:	_060_isp_done
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) 0x014:	_060_real_cas
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) 0x018:	_060_real_cas2
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) 0x01c:	_060_real_lock_page
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) 0x020:	_060_real_unlock_page
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) 0x024:	(Motorola reserved)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) 0x028:	(Motorola reserved)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) 0x02c:	(Motorola reserved)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) 0x030:	(Motorola reserved)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) 0x034:	(Motorola reserved)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) 0x038:	(Motorola reserved)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) 0x03c:	(Motorola reserved)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) 0x040:	_060_imem_read
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) 0x044:	_060_dmem_read
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) 0x048:	_060_dmem_write
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) 0x04c:	_060_imem_read_word
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) 0x050:	_060_imem_read_long
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) 0x054:	_060_dmem_read_byte
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) 0x058:	_060_dmem_read_word
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) 0x05c:	_060_dmem_read_long
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) 0x060:	_060_dmem_write_byte
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) 0x064:	_060_dmem_write_word
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) 0x068:	_060_dmem_write_long
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) 0x06c:	(Motorola reserved)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) 0x070:	(Motorola reserved)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) 0x074:	(Motorola reserved)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) 0x078:	(Motorola reserved)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) 0x07c:	(Motorola reserved)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) 68060ISP entry points:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) -----------------------
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) 0x000:	_060_isp_unimp
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) 0x008:	_060_isp_cas
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) 0x010:	_060_isp_cas2
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) 0x018:	_060_isp_cas_finish
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) 0x020:	_060_isp_cas2_finish
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) 0x028:	_060_isp_cas_inrange
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) 0x030:	_060_isp_cas_terminate
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) 0x038:	_060_isp_cas_restart
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) Integrating cas/cas2:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) ---------------------
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) The instructions "cas2" and "cas" (when used with a misaligned effective
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) address) take the Unimplemented Integer Instruction exception. When the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) 060ISP is installed properly, these instructions will enter through the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) _060_isp_unimp() entry point of the ISP.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) After the 060ISP decodes the instruction type and fetches the appropriate
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) data registers, and BEFORE the actual emulated transfers occur, the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) package calls either the "Call-out" _060_real_cas() or _060_real_cas2().
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) If the emulation code provided by the 060ISP is sufficient for the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) host system (see isp.s source code), then these "Call-out"s should be
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) made, by the system integrator, to point directly back into the package
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) through the "Entry-point"s _060_isp_cas() or _060_isp_cas2().
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187) One other necessary action by the integrator is to supply the routines
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) _060_real_lock_page() and _060_real_unlock_page(). These functions are
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) defined further in iskeleton.s and the 68060 Software Package Specification.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) If the "core" emulation routines of either "cas" or "cas2" perform some
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) actions which are too system-specific, then the system integrator must
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) supply new emulation code. This new emulation code should reside within
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194) the functions _060_real_cas() or _060_real_cas2(). When this new emulation
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195) code has completed, then it should re-enter the 060ISP package through the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196) "Entry-point" _060_isp_cas_finish() or _060_isp_cas2_finish().
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197) To see what the register state is upon entering _060_real_cas() or
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) _060_real_cas2() and what it should be upon return to the package through
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) _060_isp_cas_finish() or _060_isp_cas2_finish(), please refer to the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) source code in isp.s.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202) Miscellaneous:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) --------------
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205) _060_isp_unimp:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) ----------------
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207) - documented in 2.2 in spec.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208) - Basic flow:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209) 	exception taken ---> enter _060_isp_unimp   --|
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 210) 						      |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 211) 						      |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 212)             may exit through _060_real_itrace    <----|
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 213) 						  or  |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 214)             may exit through _060_real_chk       <----|
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 215) 						  or  |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 216)             may exit through _060_real_divbyzero <----|
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 217) 						  or  |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 218)             may exit through _060_isp_done       <----|