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# file opened: mmu.asm
1 0000 ; DOCS design (happened here, while working on it):
2 0000 ;
3 0000 ; MMU <first slot number> [<last slot number>|<single slot option>], <page number>
4 0000 ;
5 0000 ; Maps memory page(s) to slot(s), similar to SLOT + PAGE combination, but allows to set up
6 0000 ; whole range of consecutive slots (with consecutive memory pages). Or when only single
7 0000 ; slot is specified, extra option can be used to extend particular slot functionality.
8 0000 ; The slot behaviour will stay set in the current DEVICE until reset by another MMU
9 0000 ; specifying same slot (even as part of range, that will clear the option to "default").
10 0000 ;
11 0000 ; Single slot option (default state is: no error/warning and no wrap = nothing special):
12 0000 ; e = error on writing beyond last byte of slot
13 0000 ; w = warning on writing beyond last byte of slot
14 0000 ; n = wrap address back to start of slot, map next page
15 0000 ;
16 0000
17 0000 DEVICE NONE ; set "none" explicitly, to avoid "global device" feature
mmu.asm(18): warning: MMU is allowed only in real device emulation mode (See DEVICE)
18 0000 MMU ;; warning about non-device mode
19 0000 DEVICE ZXSPECTRUM128
20 0000
21 0000 ;; error messages (parsing test)
mmu.asm(22): error: [MMU] First slot number parsing failed: MMU !
22 0000 MMU !
mmu.asm(23): error: [MMU] Second slot number parsing failed: MMU 1
23 0000 MMU 1
mmu.asm(24): error: [MMU] Second slot number parsing failed: MMU 1 !
24 0000 MMU 1 !
mmu.asm(25): warning: [MMU] Unknown slot option (legal: e, w, n): x
mmu.asm(25): error: [MMU] Comma and page number expected after slot info: MMU 1 x
25 0000 MMU 1 x ; white space (or comma) after char to detect it as unknown option
mmu.asm(26): warning: [MMU] Unknown slot option (legal: e, w, n): x,
mmu.asm(26): error: [MMU] Page number parsing failed: MMU 1 x,
26 0000 MMU 1 x,
mmu.asm(27): error: [MMU] Comma and page number expected after slot info: MMU 1 1
27 0000 MMU 1 1
mmu.asm(28): error: [MMU] Page number parsing failed: MMU 0,
28 0000 MMU 0,
mmu.asm(29): error: [MMU] Page number parsing failed: MMU 0 1,
29 0000 MMU 0 1,
mmu.asm(30): error: [MMU] Page number parsing failed: MMU 0 e,
30 0000 MMU 0 e,
mmu.asm(31): error: [MMU] Page number parsing failed: MMU 0 e,!
31 0000 MMU 0 e,!
32 0000
33 0000 ;; correct syntax, invalid arguments
mmu.asm(34): error: [MMU] Requested page(s) must be in range 0..7
34 0000 MMU 0,8
mmu.asm(35): error: [MMU] Slot number(s) must be in range 0..3 and form a range
35 0000 MMU 4,0
mmu.asm(36): error: [MMU] Slot number(s) must be in range 0..3 and form a range
36 0000 MMU 3 4,0
mmu.asm(37): error: [MMU] Requested page(s) must be in range 0..7
37 0000 MMU 0 0,8
mmu.asm(38): error: [MMU] Slot number(s) must be in range 0..3 and form a range
38 0000 MMU 1 0,0
mmu.asm(39): error: [MMU] Requested page(s) must be in range 0..7
39 0000 MMU 0 2,6 ; map pages 6, 7, 8 -> 8 is wrong
40 0000
41 0000 ;; test functionality
42 0000 ; set init markers in pages 0, 5, 6 and 7
43 0000 37 37 DB "77"
43 0002 ORG 0xC000
43 C000 30 30 DB "00"
43 C002 ORG 0xC000, 5
43 C000 35 35 DB "55"
43 C002 ORG 0xC000, 6
43 C000 36 36 DB "66"
44 C002 PAGE 7
44 C002 ASSERT {0xC000} == "77"
44 C002 PAGE 6
44 C002 ASSERT {0xC000} == "66"
45 C002 PAGE 5
45 C002 ASSERT {0xC000} == "55"
45 C002 PAGE 0
45 C002 ASSERT {0xC000} == "00"
46 C002
47 C002 ; test simple page-in
48 C002 MMU 0, 5
48 C002 ASSERT {0} == "55"
49 C002 MMU 1 3, 5
49 C002 ASSERT {0x4000} == "55"
49 C002 ASSERT {0x8000} == "66"
49 C002 ASSERT {0xC000} == "77"
50 C002
51 C002 ;; test slot options (these are confined to single slot only, not to range)
52 C002 ; error option (guarding machine code write outside of current slot)
53 C002 MMU 1 e, 5
53 C002 ASSERT {0x4000} == "55"
54 C002 ORG 0x7FFF
mmu.asm(54): error: Write outside of memory slot: 32768
54 7FFF 36 73 ld (hl),'s' ; should be error, 2B opcode leaving slot memory
55 8001 ASSERT {0x8000} == "6s" ; but damage is done in the virtual memory, that's how it is
56 8001 ; while escaping from slot through ORG should be legal
57 8001 ORG 0x7FFF
57 7FFF 00 nop
57 8000 ORG 0x8000
57 8000 36 36 DB "66"
58 8002 ; changing page within tainted slot will keep the guarding ON
59 8002 SLOT 1
59 8002 PAGE 6
59 8002 ASSERT {0x4000} == "66" ; map page 6 also into slot 1
60 8002 ORG 0x7FFF
mmu.asm(60): error: Write outside of memory slot: 32768
60 7FFF 36 73 ld (hl),'s'
60 8001 ASSERT {0x8000} == "6s" ; error + damage check
61 8001
62 8001 ; verify clearing option by another MMU
63 8001 MMU 1, 5
63 8001 ASSERT {0x4000} == "55"
64 8001 ORG 0x7FFF
64 7FFF 36 36 ld (hl),'6'
64 8001 ASSERT {0x8000} == "66" ; no error
65 8001
66 8001 ; warning option (guarding machine code write outside of current slot)
67 8001 MMU 1 w, 5
67 8001 ASSERT {0x4000} == "55"
68 8001 ORG 0x7FFF
mmu.asm(68): warning: Write outside of memory slot
68 7FFF 36 73 ld (hl),'s' ; should be warning, 2B opcode leaving slot memory
69 8001 ASSERT {0x8000} == "6s" ; but damage is done in the virtual memory, that's how it is
70 8001 ; while escaping from slot through ORG should be legal
71 8001 ORG 0x7FFF
71 7FFF 00 nop
71 8000 ORG 0x8000
71 8000 36 36 DB "66"
72 8002 ; changing page within tainted slot will keep the guarding ON
73 8002 SLOT 1
73 8002 PAGE 6
73 8002 ASSERT {0x4000} == "66" ; map page 6 also into slot 1
74 8002 ORG 0x7FFF
mmu.asm(74): warning: Write outside of memory slot
74 7FFF 36 73 ld (hl),'s'
74 8001 ASSERT {0x8000} == "6s" ; warning + damage check
75 8001
76 8001 ; verify clearing option by another MMU when the slot is part of range
77 8001 MMU 0 2, 5
77 8001 ASSERT {0x4000} == "6s"
78 8001 ORG 0x7FFF
78 7FFF 36 37 ld (hl),'7'
78 8001 ASSERT {0x8000} == "77" ; no warning
79 8001
80 8001 ; next option making the memory wrap, automatically mapping in next page
81 8001 MMU 1 n, 2
82 8001 ORG 0x4000
82 4000 6E 6E 6E... BLOCK 3*16384, 'n' ; fill pages 2, 3 and 4 with 'n'
83 4000 ASSERT {0x4000} == "55" && {0x8000} == "77" ; page 5 is mapped in after that block
84 4000 SLOT 1 ; verify the block write
85 4000 PAGE 2
85 4000 ASSERT {0x4000} == "nn"
86 4000 PAGE 3
86 4000 ASSERT {0x4000} == "nn"
87 4000 PAGE 4
87 4000 ASSERT {0x4000} == "nn"
88 4000
89 4000 ; do the wrap-around test with instructions, watch labels land into different pages
90 4000 MMU 1 n, 4
91 4000