HISTORY

Z80 v0.2 (2022-XX-XX)
=====================

This is an important update that addresses a number of issues and also includes
new features. Please note that the changes introduced in this release break the
binary compatibility with the previous version.

Changes:
 1. Changed the license from GPL to LGPL (by popular request).
 2. Moved the public header from <emulation/CPU/Z80.h> to <Z80.h>.
 3. Removed the Xcode project.
 4. Switched the build system from Premake to CMake.
 5. Switched to Zeta v0.1.
 6. Added pkg-config support.
 7. Added the .vimrc dotfile.
 8. Added the CITATION.cff file.
 9. Added the file_id.diz file.
10. Added the THANKS file.
11. Added detailed documentation.
12. Added tests.
13. Added public macros for checking the library version.
14. Added public macros with bit masks for working with flags.
15. Added public macros for accessing the 16-bit registers.
16. Added the z80_execute function to run a simplified emulation without RESET
    and interrupts.
17. Added the z80_refresh_address function to get the refresh address of the
    current M1 cycle.
18. Added the z80_in_cycle and z80_out_cycle functions to get the clock cycle on
    which the I/O M-cycle occurs, relative to the start of the instruction.
19. Fixed a bug in the "sll" instruction.
20. Fixed a bug in the INX and OUTX macros affecting the S and N flags.
21. Fixed a bug in the OUTX macro affecting the MSByte of the port number.
22. Fixed the clock cycles of the "dec XY" and "in (c)" instructions.
23. Fixed the read_16 function so that the order in which the compiler evaluates
    expressions does not affect the order of the memory read operations.
24. Fixed the order in which the memory write operations are performed when the
    SP register is involved. This affects the NMI response, the INT response in
    modes 1 and 2, and the following instructions: "ex (sp),{hl|XY}", "push TT",
    "push XY", "call WORD", "call Z,WORD" and "rst N".
25. Fixed the handling of illegal instructions to avoid stack overflows in long
    sequences of DDh/FDh prefixes.
26. Fixed several implicit conversions to avoid warnings about loss of sign and
    precision.
27. Fixed some bitwise operations to avoid undefined behavior and arithmetic
    right shifts on signed integers.
28. Fixed violations of the C standard in several identifiers.
29. Renamed the 8-bit register lists: X/Y to J/K; J/K and P/Q to O/P.
30. Replaced all P/V overflow computation functions with a single, faster macro.
31. Replaced all register resolution functions with macros.
32. Replaced all "ld {J,K|O,P}" instructions that have the same destination and
    source register with NOPs.
33. Reimplemented the HALT state. The emulation should now be fully accurate.
    HALTskip is also supported.
34. Added optional emulation of the normal and special RESET signals, along with
    the new z80_reset and z80_special_reset functions to emit them. The old
    z80_reset function is now called z80_instant_reset.
35. Added the Z80::fetch_opcode and Z80::fetch callbacks to perform opcode fetch
    operations and memory read operations on instruction data respectively.
36. Added the Z80::nop callback to perform disregarded opcode fetch operations
    during internal NOP M-cycles.
37. Added emulation of the NMI acknowledge M-cycle through the new Z80::nmia
    callback.
38. Added emulation of the INT acknowledge M-cycle through the new Z80::inta
    callback, which replaces Z80::int_data.
39. Added optional full emulation of the interrupt mode 0, along with the new
    Z80::int_fetch callback to perform bus read operations on instruction data.
    If not enabled at compile-time, the old simplified emulation is built, which
    supports only the most typical instructions.
40. Added four callbacks to notify the execution of important instructions:
    Z80::ld_i_a, Z80::ld_r_a, Z80::reti and Z80::retn.
41. Added hooking functionality through the "ld h,h" instruction and the new
    Z80::hook callback.
42. Added the Z80::illegal callback to delegate the emulation of illegal
    instructions.
43. Added accurate flag behavior in the following instructions: "ldir", "lddr",
    "cpir", "cpdr", "inir", "indr", "otir" and "otdr".
44. Added emulation of the interrupt acceptance deferral that occurs during the
    "reti" and "retn" instructions.
45. Added MEMPTR emulation. The "bit N,(hl)" instruction now produces a correct
    value of F.
46. Added optional emulation of the Q "register". If enabled at compile-time,
    the "ccf" and "scf" instructions produce a correct value of F.
47. Added emulation options that can be configured at runtime.
48. Added emulation of the "out (c),255" instruction (Zilog Z80 CMOS).
49. Added optional emulation of the bug affecting the "ld a,{i|r}" instructions
    (Zilog Z80 NMOS). If enabled at compile-time, the P/V flag is reset when an
    INT is accepted during the execution of these instructions.
50. Removed Z80::state. Replaced with individual members for the registers, the
    interrupt enable flip-flops and the interrupt mode.
51. Removed the superfluous EI flag. The previous opcode is checked instead,
    which is faster and makes the Z80 object smaller.
52. Removed all module-related stuff.
53. Optimizations in flag computation and condition evaluation.
54. New source code comments and improvements to existing ones.
55. Improved code aesthetics.
56. Other improvements, optimizations and minor changes.


Z80 v0.1 (2018-11-10)
=====================

Initial public release.