RX/TX int: Improve register allocation. TX int: Simplify/optimize flag handling.

[z180-stamp-cpm3.git] / cbios / ascii.180

diff --git a/cbios/ascii.180 b/cbios/ascii.180
index e75dd87098d1386de5aff2049fd9ef9f2f7cd357..2353ae00b093e3437b6dbd6d771489f385f8b117 100644 (file)
--- a/cbios/ascii.180
+++ b/cbios/ascii.180
@@ -591,7 +591,7 @@ asci1_inp:
        di\r
        set     TDC1,(ix+oint.stat)     ;\r
        in0     a,(stat1)               ;\r
-       or      M_TIE,                  ;\r
+       or      M_TIE                   ;\r
        out0    (stat1),a               ;\r
        ei\r
 a1i_2:\r
@@ -673,35 +673,35 @@ asci_int macro    dev
        local   rxi_2,rxi_3\r
 \r
        push    ix\r
-rxtxi&dev&_lp0:\r
        ld      ix,s&dev&.inbuf         ;\r
+       ld      d,(ix+oint.fflags)\r
 rxtxi&dev&_lp1:\r
-       in0     a,(stat&dev)            ;receive flag set?\r
+       in0     e,(stat&dev)            ;get asci status\r
        jp      p,txi&dev               ;RDRF == Bit 7\r
-       and     M_OVRN+M_PERR+M_FE\r
-       ld      e,a\r
 \r
-       in0     a,(asext&dev)\r
+       ; RX Interrupt\r
+\r
+       res     BREAK,e\r
+       in0     a,(asext&dev)           ;get break status\r
        and     M_BREAK\r
-       or      e\r
+       or      e                       ;merge to other error flags\r
        ld      e,a\r
 \r
-       in0     d,(cntla&dev)           ;\r
-       res     EFR,d                   ;\r
-       out0    (cntla&dev),d\r
+       in0     a,(cntla&dev)           ;reset all error flags\r
+       and     ~M_EFR                  ;\r
+       out0    (cntla&dev),a           ;\r
 \r
        ld      c,(ix+o.in_idx)         ;input buffer pointer\r
        ld      b,0\r
        ld      hl,s&dev&.inbuf         ;\r
        add     hl,bc\r
 \r
-       in0     a,(rdr&dev)             ;get char\r
-       ld      (hl),a\r
+       in0     b,(rdr&dev)             ;get char\r
                                        ;todo: break detection\r
-                                       ;todo: parity, framing overrun error\r
+                                       ;todo: parity, framing, overrun error\r
+       ld      (hl),b\r
 \r
-       ld      e,(ix+oint.fflags)\r
-;      bit     IXON,e\r
+;      bit     IXON,d\r
 ;      jr      z,rxi_2\r
                                        ;todo: test XON/XOFF\r
 rxi_2:\r
@@ -724,46 +724,42 @@ rxi_2:
        jr      nz,rxtxi&dev&_lp1\r
 \r
    if dev=0                            ; only channel 0 has rts line\r
-       bit     CRTS_IFLOW,e\r
+       bit     CRTS_IFLOW,d\r
        jr      z,rxi0_nocrts\r
 \r
-       set     EFR,d\r
-       set     RTS0,d                  ;RTS inactive\r
-       out0    (cntla0),d              ;\r
+       in0     a,(cntla&dev)           ;reset all error flags\r
+       or      M_RTS0+M_EFR                    ;RTS inactive\r
+       out0    (cntla0),a              ;\r
 rxi0_nocrts:\r
    endif\r
 \r
-       bit     IXOFF,e\r
+       bit     IXOFF,d\r
        jr      z,rxtxi&dev&_lp1\r
                                        ;send XOFF\r
        set     TDC3,(ix+oint.stat)\r
-       in0     a,(stat&dev)            ;\r
-       set     TIE,a                   ;\r
-       out0    (stat&dev),a            ;\r
+       set     TIE,e                   ;\r
+       out0    (stat&dev),e            ;\r
        jr      rxtxi&dev&_lp1\r
 \r
 txi&dev:\r
-       ld      e,a\r
        bit     TDRE,e                  ;TX int?\r
        jr      z,rxtxi&dev&_exit\r
-                                       ;todo: xon/xoff\r
-       bit     IXOFF,(ix+oint.fflags)\r
-       jr      z,txi&dev&_char\r
-txi&dev&_dc1:\r
-       bit     TDC1,(ix+oint.stat)\r
-       jr      z,txi&dev&_dc3\r
-       res     TDC1,(ix+oint.stat)\r
-       ld      a,DC1\r
-       jr      txi&dev&_dc1dc3\r
-\r
-txi&dev&_dc3:\r
-       bit     TDC3,(ix+oint.stat)\r
-       jr      z,txi&dev&_char\r
-       res     TDC3,(ix+oint.stat)\r
-       ld      a,DC3\r
-txi&dev&_dc1dc3:\r
-       out0    (tdr&dev),a             ;\r
-       jp      rxtxi&dev&_lp0\r
+\r
+       ; TX Interrupt\r
+\r
+       ld      a,(ix+oint.stat)        ;check if xon/xoff should be sent\r
+       tst     M_TDC1+M_TDC3           ;\r
+       jr      z,txi&dev&_char         ;  no\r
+\r
+       ld      l,DC3                   ;prepare for xoff\r
+       bit     TDC1,a                  ;request for xon (also) set?\r
+       jr      z,txi&dev&_cch          ;\r
+       ld      l,DC1                   ;\r
+txi&dev&_cch:\r
+       out0    (tdr&dev),l             ;\r
+       and     ~(M_TDC1+M_TDC3)        ;reset request flags\r
+       ld      (ix+oint.stat),a        ;\r
+       jp      rxtxi&dev&_lp1          ;\r
 \r
 txi&dev&_char:\r
        ld      hl,s&dev&.outbuf+o.in_idx       ;[in]\r
@@ -782,7 +778,7 @@ txi&dev&_char:
        and     c                       ;\r
        ld      (s&dev&.outbuf+o.out_idx),a     ;\r
 \r
-       jp      rxtxi&dev&_lp0\r
+       jp      rxtxi&dev&_lp1\r
 \r
 txi&dev&_empty:\r
        res     TIE,e                   ;disable tx-int\r