z80_as.1 2.1 KB

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  1. .\" $Header$
  2. .TH z80_AS 1
  3. .ad
  4. .SH NAME
  5. z80_as \- assembler for Zilog z80
  6. .SH SYNOPSIS
  7. /usr/em/lib/z80_as [options] argument ...
  8. .SH DESCRIPTION
  9. This assembler is made with the general framework
  10. described in \fIuni_ass\fP(6).
  11. .SH SYNTAX
  12. .IP registers
  13. The z80 has six general-purpose 8-bit registers: b, c, d, e, h, l;
  14. an 8-bit accumulator: a; an 8-bit flag register: f; an 8-bit interrupt
  15. vector: i; an 8-bit memory refresh register: r; two 16-bit index registers:
  16. ix, iy; a 16-bit stack pointer: sp; and a 16-bit program counter: pc.
  17. The general-purpose registers can be paired to form three registers pairs of
  18. 16 bits each: bc, de, hl.
  19. An alternate set of registers is provided that duplicates the accumulator,
  20. the flag register, and the general-purpose registers. The "exx"-instruction
  21. exchanges the contents of the two sets of general-purpose registers; the
  22. contents of the accumulator and flag register can be exchanged with the contents
  23. of their alternates by the "ex af, af2"-instruction.
  24. .IP "addressing modes"
  25. .nf
  26. .ta 8 16 24 32 40 48
  27. syntax meaning
  28. expr dependent on the instruction, the
  29. value of `expr' can be immediate
  30. data or the address of the operand.
  31. There is no special notation for
  32. immediate data.
  33. (ireg + expr)
  34. (ireg - expr) the contents of ireg (which must be
  35. one of the index-registers) + or -
  36. the - one byte - value of `expr'
  37. yield the address of the operand.
  38. (expr) the value of `expr' is the address of
  39. the operand.
  40. reg the contents of `reg' - one of the above-
  41. mentioned registers - is the operand.
  42. (reg) the contents of `reg' - one of the 16-bit
  43. registers except pc - is the address of
  44. the operand.
  45. nz, z, nc, c,
  46. po, pe, p, m the letters indicate a condition-code:
  47. nonzero, zero, carry, no carry,
  48. parity odd, parity even, sign positive,
  49. sign negative respectively. Used by conditional
  50. jump, call, and return instructions.
  51. .fi
  52. .IP instructions
  53. The jr-instruction will automatically be replaced by a jp-instruction if the
  54. target is too remote.
  55. .SH "SEE ALSO"
  56. uni_ass(6),
  57. ack(1),
  58. .br
  59. Z80 Users Manual, Joseph J. Carr, Reston Publishing Company, 1980