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mc6854.cpp: small cleanup for readability

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Joakim Larsson Edstrom 2019-11-21 12:15:12 +01:00
parent c449662983
commit d5b919eae3
1 changed files with 24 additions and 62 deletions
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86
src/devices/machine/mc6854.cpp
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@ -57,92 +57,54 @@ constexpr unsigned mc6854_device::MAX_FRAME_LENGTH;
/* control register 1 */
#define AC ( m_cr1 & 1 )
#define AC ( m_cr1 & 1 ) /* extra register select bits */
#define FCTDRA ( m_cr2 & 8 )
/* extra register select bits */
#define RRESET ( m_cr1 & 0x40 )
#define RRESET ( m_cr1 & 0x40 ) /* transmit / reset condition */
#define TRESET ( m_cr1 & 0x80 )
/* transmit / reset condition */
#define RIE ( m_cr1 & 2 )
#define RIE ( m_cr1 & 2 ) /* interrupt enable */
#define TIE ( m_cr1 & 4 )
/* interrupt enable */
#define DISCONTINUE ( m_cr1 & 0x20 )
/* discontinue received frame */
#define DISCONTINUE ( m_cr1 & 0x20 ) /* discontinue received frame */
/* control register 2 */
#define PSE ( m_cr2 & 1 )
/* prioritize status bits (TODO) */
#define TWOBYTES ( m_cr2 & 2 )
/* two-bytes mode */
#define FMIDLE ( m_cr2 & 4 )
/* flag time fill (vs. mark idle) */
#define TLAST ( m_cr2 & 0x10 )
/* transmit last byte of frame */
#define RTS ( m_cr2 & 0x80 )
/* request-to-send */
#define PSE ( m_cr2 & 1 ) /* prioritize status bits (TODO) */
#define TWOBYTES ( m_cr2 & 2 ) /* two-bytes mode */
#define FMIDLE ( m_cr2 & 4 ) /* flag time fill (vs. mark idle) */
#define TLAST ( m_cr2 & 0x10 ) /* transmit last byte of frame */
#define RTS ( m_cr2 & 0x80 ) /* request-to-send */
/* control register 3 */
#define LCF ( m_cr3 & 1 )
/* logical control field select */
#define CEX ( m_cr3 & 2 )
/* control field is 16 bits instead of 8 */
#define AEX ( m_cr3 & 4 )
/* extended address mode (vs normal 8-bit address mode) */
#define IDL0 ( m_cr3 & 8 )
/* idle condition begins with a '0' instead of a '1" */
#define FDSE ( m_cr3 & 0x10 )
/* enable the flag detect status in SR1 */
#define LOOP ( m_cr3 & 0x20 )
/* loop mode */
#define TST ( m_cr3 & 0x40 )
/* test mode (or go active on poll) */
#define DTR ( m_cr3 & 0x80 )
/* data-transmit-ready (or loop on-line control) */
#define LCF ( m_cr3 & 1 ) /* logical control field select */
#define CEX ( m_cr3 & 2 ) /* control field is 16 bits instead of 8 */
#define AEX ( m_cr3 & 4 ) /* extended address mode (vs normal 8-bit address mode) */
#define IDL0 ( m_cr3 & 8 ) /* idle condition begins with a '0' instead of a '1" */
#define FDSE ( m_cr3 & 0x10 ) /* enable the flag detect status in SR1 */
#define LOOP ( m_cr3 & 0x20 ) /* loop mode */
#define TST ( m_cr3 & 0x40 ) /* test mode (or go active on poll) */
#define DTR ( m_cr3 & 0x80 ) /* data-transmit-ready (or loop on-line control) */
/* control register 4 */
#define TWOINTER ( m_cr4 & 1 )
/* both an openning and a closing inter-frame are sent */
#define TWOINTER ( m_cr4 & 1 ) /* both an openning and a closing inter-frame are sent */
static const int word_length[4] = { 5, 6, 7, 8 };
static const int word_length[4] = { 5, 6, 7, 8 }; /* transmit / receive word length */
#define TWL word_length[ ( m_cr4 >> 1 ) & 3 ]
#define RWL word_length[ ( m_cr4 >> 3 ) & 3 ]
/* transmit / receive word length */
#define ABT ( m_cr4 & 0x20 )
/* aborts */
#define ABTEX ( m_cr4 & 0x40 )
/* abort generates 16 '1' bits instead of 8 */
#define NRZ ( m_cr4 & 0x80 )
/* zero complement / non-zero complement data format */
#define ABT ( m_cr4 & 0x20 ) /* aborts */
#define ABTEX ( m_cr4 & 0x40 ) /* abort generates 16 '1' bits instead of 8 */
#define NRZ ( m_cr4 & 0x80 ) /* zero complement / non-zero complement data format */
/* status register 1 */
#define RDA 0x01 /* receiver data available */
#define S2RQ 0x02 /* status register #2 read request */
#define FD 0x04 /* flag detect */
@ -153,6 +115,7 @@ static const int word_length[4] = { 5, 6, 7, 8 };
/* status register 2 */
#define AP 0x01 /* address present */
#define FV 0x02 /* frame valid */
#define RIDLE 0x04 /* receiver idle */
@ -163,7 +126,6 @@ static const int word_length[4] = { 5, 6, 7, 8 };
#define RDA2 0x80 /* copy of RDA */
DEFINE_DEVICE_TYPE(MC6854, mc6854_device, "mc6854", "Motorola MC6854 ADLC")
mc6854_device::mc6854_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) :