Rev. 1.00, 05/04, page 24 of 544
2.4.4
Condition-Code Register (CCR)
This 8-bit register contains internal CPU status information, including an interrupt mask bit (I) and
half-carry (H), negative (N), zero (Z), overflow (V), and carry (C) flags. Operations can be
performed on the CCR bits by the LDC, STC, ANDC, ORC, and XORC instructions. The N, Z, V,
and C flags are used as branching conditions for conditional branch (Bcc) instructions.
Bit Bit
Name
Initial
Value R/W Description
7
I
1
R/W
Interrupt Mask Bit
Masks interrupts other than NMI when set to 1. NMI is
accepted regardless of the I bit setting. The I bit is set
to 1 at the start of an exception-handling sequence. For
details, refer to section 5, Interrupt Controller.
6
UI
Undefined R/W
User Bit or Interrupt Mask Bit
Can be written to and read from by software using the
LDC, STC, ANDC, ORC, and XORC instructions.
5 H Undefined
R/W
Half-Carry
Flag
When the ADD.B, ADDX.B, SUB.B, SUBX.B, CMP.B or
NEG.B instruction is executed, this flag is set to 1 if
there is a carry or borrow at bit 3, and cleared to 0
otherwise. When the ADD.W, SUB.W, CMP.W, or
NEG.W instruction is executed, the H flag is set to 1 if
there is a carry or borrow at bit 11, and cleared to 0
otherwise. When the ADD.L, SUB.L, CMP.L, or NEG.L
instruction is executed, the H flag is set to 1 if there is a
carry or borrow at bit 27, and cleared to 0 otherwise.
4 U Undefined
R/W
User
Bit
Can be written to and read from by software using the
LDC, STC, ANDC, ORC, and XORC instructions.
3 N Undefined
R/W
Negative
Flag
Stores the value of the most significant bit of data as a
sign bit.
2 Z Undefined
R/W
Zero
Flag
Set to 1 to indicate zero data, and cleared to 0 to
indicate non-zero data.
1 V Undefined
R/W
Overflow
Flag
Set to 1 when an arithmetic overflow occurs, and
cleared to 0 otherwise.
Содержание H8S/2111B
Страница 2: ...Rev 1 00 05 04 page ii of xxxiv...
Страница 8: ...Rev 1 00 05 04 page viii of xxxiv...
Страница 22: ...Rev 1 00 05 04 page xxii of xxxiv...
Страница 30: ...Rev 1 00 05 04 page xxx of xxxiv...
Страница 84: ...Rev 1 00 05 04 page 50 of 544...
Страница 100: ...Rev 1 00 05 04 page 66 of 544...
Страница 126: ...Rev 1 00 05 04 page 92 of 544...
Страница 180: ...Rev 1 00 05 04 page 146 of 544...
Страница 216: ...Rev 1 00 05 04 page 182 of 544...
Страница 254: ...Rev 1 00 05 04 page 220 of 544...
Страница 268: ...Rev 1 00 05 04 page 234 of 544...
Страница 382: ...Rev 1 00 05 04 page 348 of 544...
Страница 462: ...Rev 1 00 05 04 page 428 of 544...
Страница 464: ...Rev 1 00 05 04 page 430 of 544...
Страница 488: ...Rev 1 00 05 04 page 454 of 544...
Страница 496: ...Rev 1 00 05 04 page 462 of 544...
Страница 574: ...Rev 1 00 05 04 page 540 of 544...
Страница 581: ......
Страница 582: ...H8S 2111B Hardware Manual...