@ -61,14 +61,74 @@ MINIT:
CALL IDBIO ; 1=HBIOS, 2=UBIOS
LD (BIOID),A ; Save it
DEC A ; Test for HBIOS
JR Z,HINIT ; Do HBIOS setup
JR Z,MINIT_HB ; Do HBIOS setup
DEC A ; Test for UBIOS
JR Z,UINIT ; Do UBIOS setup
JR Z,MINIT_UB ; Do UBIOS setup
;
; Neither UNA nor RomWBW
LD DE,ERR_BIO ; BIOS error message
JP FAIL ; Print msg and bail out
;
MINIT_HB:
; Display RomWBW notification string
LD DE,HB_TAG ; BIOS notification string
LD C,9 ; BDOS string display function
CALL BDOS ; Do it
;
; Get CPU speed from RomWBW HBIOS and save it
LD B,0F8H ; HBIOS SYSGET function 0xF8
LD C,0F0H ; CPUINFO subfunction 0xF0
RST 08 ; Do it, L := CPU speed in MHz
LD A,L ; Move it to A
LD (CPUSPD),A ; Save it
;
; Get HBIOS bank id
LD BC,0F8F2H ; HBIOS SYSGET, Bank Info
RST 08 ; do it
JP NZ,APIERR ; handle API error
LD A,D ; BIOS bank id to A
LD (BIOSBID),A ; save it
;
; Lookup current console to use as default for transfer
LD B,0FAH ; HBIOS PEEK
LD A,(BIOSBID) ; get BIOS bank id
LD D,A ; ... and put in D
LD HL,100H + 12H ; HCB console unit address
RST 08 ; E := value
LD A,E ; put in A
LD (UNIT),A ; save it
;
; Get HBIOS character 0 device type
LD B,006H ; HBIOS DEVICE function 0x06
LD C,000H ; HBIOS char 0 device
RST 08 ; Do it, D=device type
LD A,D ; Put result in A
CP 000H ; UART?
JP Z,UA_INIT ; If so, do UART H/W init
CP 080H ; USB-FIFO?
JP Z,UF_INIT ; If so, do USB-FIFO H/W init
JP HB_INIT ; Otherwise, use BIOS I/O
;
MINIT_UB:
; Display UNA notification string
LD DE,UB_TAG ; BIOS notification string
LD C,9 ; BDOS string display function
CALL BDOS ; Do it
;
; Get CPU speed from UNA and save it
LD C,0F8H ; UNA BIOS Get PHI function
RST 08 ; Returns speed in Hz in DE:HL
LD B,4 ; Divide MHz in DE:HL by 100000H
MINIT_UB1:
SRL D ; ... to get approx CPU speed in
RR E ; ...MHz. Throw away HL, and
DJNZ MINIT_UB1 ; ...right shift DE by 4.
INC E ; Fix up for value truncation
LD A,E ; Put in A
LD (CPUSPD),A ; Save it
;
JP UB_INIT ; UNA BIOS init
;
MINIT_RET:
PUSH HL ; Save HL (JP table adr)
@ -107,45 +167,35 @@ MINIT_RET:
LD HL,(RCVSCL) ; HL := receive scalar
RET ; and return
;
HINIT:
; Display RomWBW notification string
LD DE,HBTAG ; BIOS notification string
LD C,9 ; BDOS string display function
CALL BDOS ; Do it
;
; Get CPU speed from RomWBW HBIOS and save it
LD B,0F8H ; HBIOS SYSGET function 0xF8
LD C,0F0H ; CPUINFO subfunction 0xF0
RST 08 ; Do it, L := CPU speed in MHz
LD A,L ; Move it to A
LD (CPUSPD),A ; Save it
;
JP H_INIT ; HBIOS init
;-----------------------------------------------------------------------
;
UINIT:
; Display UNA notification string
LD DE,UBTAG ; BIOS notification string
LD C,9 ; BDOS string display function
CALL BDOS ; Do it
; Uninitialize modem
;
; Get CPU speed from UNA and save it
LD C,0F8H ; UNA BIOS Get PHI function
RST 08 ; Returns speed in Hz in DE:HL
LD B,4 ; Divide MHz in DE:HL by 100000H
UINIT1:
SRL D ; ... to get approx CPU speed in
RR E ; ...MHz. Throw away HL, and
DJNZ UINIT1 ; ...right shift DE by 4.
INC E ; Fix up for value truncation
LD A,E ; Put in A
LD (CPUSPD),A ; Save it
UNINIT:
LD A,(BIOID)
CP 1 ; Is HBIOS?
JR Z,HUNINIT ; Handle HBIOS
CP 2 ; Is UBIOS?
JR Z,UUNINIT ; Handle UBIOS
RET ; Just return
;
JP U_INIT ; UNA BIOS init
HUNINIT:
; HBIOS: Reset character device 0
LD B,04H ; HBIOS CIOINIT function 0x04
LD A,(UNIT) ; HBIOS serial unit number
LD C,A ; Put in C for func call
LD DE,-1 ; Reset w/ current settings
RST 08 ; Do it
RET ; not initialized, so no 'UN-INITIALIZE'
;
HWERR:
; Failed to identify target comm hardware
LD DE,ERR_HW ; Hardware error message
JP FAIL ; Print message and bail out
UUNINIT:
; UBIOS: Reset character device 0
LD C,10H ; UNA INIT function 0x10
LD A,(UNIT) ; UBIOS serial unit number
LD B,A ; Put in B for func call
LD DE,-1 ; Reset w/ current settings
RST 08 ; Do it
RET ; not initialized, so no 'UN-INITIALIZE'
;
; Identify active BIOS. RomWBW HBIOS=1, UNA UBIOS=2, else 0
;
@ -184,6 +234,16 @@ IDBIO2:
XOR A ; Setup return value of 0
RET ; and done
;
HWERR:
; Failed to identify target comm hardware
LD DE,ERR_HW ; Hardware error message
JP FAIL ; Print message and bail out
;
APIERR:
; API returned unepected failure
LD DE,ERR_API ; API error message
JP FAIL ; Pprint message and bail out
;
FAIL:
; DE has error string address
LD C,9 ; BDOS string display function
@ -192,36 +252,6 @@ FAIL:
;
;-----------------------------------------------------------------------
;
; Uninitialize modem
;
UNINIT:
LD A,(BIOID)
CP 1 ; Is HBIOS?
JR Z,H_UNINIT ; Handle HBIOS
CP 2 ; Is UBIOS?
JR Z,U_UNINIT ; Handle UBIOS
RET ; Just return
;
H_UNINIT:
; HBIOS: Reset character device 0
LD B,04H ; HBIOS CIOINIT function 0x04
LD A,(UNIT) ; HBIOS serial unit number
LD C,A ; Put in C for func call
LD DE,-1 ; Reset w/ current settings
RST 08 ; Do it
RET ; not initialized, so no 'UN-INITIALIZE'
;
U_UNINIT:
; UBIOS: Reset character device 0
LD C,10H ; UNA INIT function 0x10
LD A,(UNIT) ; UBIOS serial unit number
LD B,A ; Put in B for func call
LD DE,-1 ; Reset w/ current settings
RST 08 ; Do it
RET ; not initialized, so no 'UN-INITIALIZE'
;
;-----------------------------------------------------------------------
;
; The following are all dummy routines that are unused because MINIT
; dynamically installs the real jump table.
;
@ -240,17 +270,20 @@ EXTRA3:
BIOID DB 0 ; BIOS ID, 1=HBIOS, 2=UBIOS
CPUSPD DB 10 ; CPU speed in MHz
RCVSCL DW 6600 ; RECV loop timeout scalar
UNIT DB 0 ; HBIOS serial device unit number
UNIT DB 0 ; BIOS serial device unit number
BIOSBID DB 00H ; BIOS bank id
;
TAG DB "RomWBW, 23-May-2020$"
;
H_LBL DB ", HBIOS FastPath$"
U_LBL DB ", UNA UBIOS$"
HB_LBL DB ", HBIOS FastPath$"
UB_LBL DB ", UNA UBIOS$"
UA_LBL DB ", UART$"
UF_LBL DB ", USB-FIFO$"
COM_LBL DB " on COM$"
EXP_LBL DB 13, 10, 13, 10, "*** Experimental ***$"
;
UBTAG DB " [UNA]$"
HBTAG DB " [WBW]$"
UB_ TAG DB " [UNA]$"
HB_ TAG DB " [WBW]$"
;
CRLF DB 13, 10, "$"
;
@ -270,38 +303,22 @@ ERR_API DB 13, 10, 13, 10, "++ BIOS API Error ++", 13, 10, "$"
; table at program startup. See MINIT above. Note that only a
; subset of the jump table is overlaid (SENDR to SPEED).
;
H_JPTBL:
JP H_SENDR ; send character (via pop psw)
JP H_CAROK ; test for carrier
JP H_MDIN ; receive data byte
JP H_GETCHR ; get character from modem
JP H_RCVRDY ; check receive ready
JP H_SNDRDY ; check send ready
JP H_SPEED ; get speed value for file transfer time
HB _JPTBL:
JP HB _SENDR ; send character (via pop psw)
JP HB _CAROK ; test for carrier
JP HB _MDIN ; receive data byte
JP HB _GETCHR ; get character from modem
JP HB _RCVRDY ; check receive ready
JP HB _SNDRDY ; check send ready
JP HB _SPEED ; get speed value for file transfer time
;
;-----------------------------------------------------------------------
;
; HBIOS initialization
;
H_INIT:
HB _INIT:
LD HL,2150 ; Smaller receive loop timeout scalar
LD (RCVSCL),HL ; ... to compensate for BIOS overhead
;
; Get HBIOS bank id
LD BC,0F8F2H ; HBIOS SYSGET, Bank Info
RST 08 ; do it
JR NZ,H_APIERR ; handle API error
LD A,D ; BIOS bank id to A
LD (H_BNKID),A ; save it
;
; Lookup current console to use as default for transfer
LD B,0FAH ; HBIOS PEEK
LD A,(H_BNKID) ; get BIOS bank id
LD D,A ; ... and put in D
LD HL,100H + 12H ; HCB console unit address
RST 08 ; E := value
LD A,E ; put in A
LD (UNIT),A ; save it
;
; Patch SENDR w/ FastPath addresses
LD BC,0F801H ; Get CIO func/data adr
@ -309,9 +326,9 @@ H_INIT:
LD A,(UNIT) ; get desired char unit
LD E,A ; and put in E
RST 08
JR NZ,H_ APIERR ; handle API error
LD (H_UDAT),DE ; Plug in data adr
LD (H_SCFN),HL ; Plug in func adr
JP NZ, APIERR ; handle API error
LD (HB _UDAT),DE ; Plug in data adr
LD (HB _SCFN),HL ; Plug in func adr
;
; Patch GETCHR/MDIN w/ FastPath addresses
LD BC,0F801H ; Get CIO func/data adr
@ -319,8 +336,8 @@ H_INIT:
LD A,(UNIT) ; get desired char unit
LD E,A ; and put in E
RST 08
JR NZ,H_ APIERR ; handle API error
LD (H_GCFN),HL ; Plug in func adr
JP NZ, APIERR ; handle API error
LD (HB _GCFN),HL ; Plug in func adr
;
; Patch RCVRDY w/ FastPath addresses
LD BC,0F801H ; Get CIO func/data adr
@ -328,8 +345,8 @@ H_INIT:
LD A,(UNIT) ; get desired char unit
LD E,A ; and put in E
RST 08
JR NZ,H_ APIERR ; handle API error
LD (H_RRFN),HL ; Plug in func adr
JP NZ, APIERR ; handle API error
LD (HB _RRFN),HL ; Plug in func adr
;
; Patch SNDRDY w/ FastPath addresses
LD BC,0F801H ; Get CIO func/data adr
@ -337,31 +354,27 @@ H_INIT:
LD A,(UNIT) ; get desired char unit
LD E,A ; and put in E
RST 08
JR NZ,H_ APIERR ; handle API error
LD (H_SRFN),HL ; Plug in func adr
JP NZ, APIERR ; handle API error
LD (HB _SRFN),HL ; Plug in func adr
;
LD HL,H_JPTBL
LD DE,H_LBL
LD HL,HB _JPTBL
LD DE,HB _LBL
JP MINIT_RET
;
H_APIERR:
LD DE,ERR_API
JP FAIL
;
;-----------------------------------------------------------------------
;
; Send character on top of stack
;
H_SENDR:
HB _SENDR:
POP AF ; get character to send from stack
PUSH BC
PUSH DE
PUSH HL
LD E,A ; character to E
LD IY,(H_UDAT)
LD A,(H_BNK ID) ; call into HBIOS bank
LD IY,(HB _UDAT)
LD A,(BIOSB ID) ; call into HBIOS bank
LD IX,0000H
H_SCFN EQU $-2
HB _SCFN EQU $-2
CALL 0FFF9H ; HBIOS bank call
POP HL
POP DE
@ -372,28 +385,31 @@ H_SCFN EQU $-2
;
; Test and report carrier status, Z set if carrier present
;
H_CAROK:
HB _CAROK:
XOR A ; not used, always indicate present
RET
;
;-----------------------------------------------------------------------
;
; Get a character (assume character ready has already been tested)
; Get a character
;
; GETCHR must NOT block.
; GETCHR must not block
;
H_GETCHR:
CALL H_RCVRDY
HB _GETCHR:
CALL HB _RCVRDY
RET NZ
H_MDIN:
; Fall thru if char ready
;
; MDIN can assume a character is ready
;
HB_MDIN:
PUSH BC
PUSH DE
PUSH HL
LD IY,(H_UDAT)
LD A,(H_BNK ID) ; call into HBIOS bank
LD IY,(HB _UDAT)
LD A,(BIOSB ID) ; call into HBIOS bank
LD IX,0000H
H_GCFN EQU $-2
HB _GCFN EQU $-2
CALL 0FFF9H ; HBIOS bank call
LD A,E ; byte received to A
POP HL
@ -407,14 +423,14 @@ H_GCFN EQU $-2
; Error code returned in A register
; *** Error code does not seem to be used ***
;
H_RCVRDY:
HB _RCVRDY:
PUSH BC
PUSH DE
PUSH HL
LD IY,(H_UDAT)
LD A,(H_BNK ID) ; call into HBIOS bank
LD IY,(HB _UDAT)
LD A,(BIOSB ID) ; call into HBIOS bank
LD IX,0000H
H_RRFN EQU $-2
HB _RRFN EQU $-2
CALL 0FFF9H ; HBIOS bank call
SUB 1 ; CF set IFF zero
RL A ; CF to bit 0 of A
@ -429,14 +445,14 @@ H_RRFN EQU $-2
;
; Test for ready to send a character, Z = ready
;
H_SNDRDY:
HB _SNDRDY:
PUSH BC
PUSH DE
PUSH HL
LD IY,(H_UDAT)
LD A,(H_BNK ID) ; call into HBIOS bank
LD IY,(HB _UDAT)
LD A,(BIOSB ID) ; call into HBIOS bank
LD IX,0000H
H_SRFN EQU $-2
HB _SRFN EQU $-2
CALL 0FFF9H ; HBIOS bank call
SUB 1 ; CF set IFF zero
RL A ; CF to bit 0 of A
@ -450,14 +466,13 @@ H_SRFN EQU $-2
;
; Report baud rate (index into SPTBL returned in register A)
;
H_SPEED:
HB _SPEED:
LD A,8 ; arbitrarily return 9600 baud
RET
;
;
;
H_BNKID DB 00H ; HBIOS bank id
H_UDAT DW 0000H ; Unit data address
HB_UDAT DW 0000H ; Unit data address
;
;
;=======================================================================
@ -472,20 +487,20 @@ H_UDAT DW 0000H ; Unit data address
; table at program startup. See MINIT above. Note that only a
; subset of the jump table is overlaid (SENDR to SPEED).
;
U_JPTBL:
JP U_SENDR ; send character (via pop psw)
JP U_CAROK ; test for carrier
JP U_MDIN ; receive data byte
JP U_GETCHR ; get character from modem
JP U_RCVRDY ; check receive ready
JP U_SNDRDY ; check send ready
JP U_SPEED ; get speed value for file transfer time
UB _JPTBL:
JP UB _SENDR ; send character (via pop psw)
JP UB _CAROK ; test for carrier
JP UB _MDIN ; receive data byte
JP UB _GETCHR ; get character from modem
JP UB _RCVRDY ; check receive ready
JP UB _SNDRDY ; check send ready
JP UB _SPEED ; get speed value for file transfer time
;
;-----------------------------------------------------------------------
;
; UBIOS initialization
;
U_INIT:
UB _INIT:
;
; TODO:
; - TEST!!!
@ -494,15 +509,15 @@ U_INIT:
LD HL,3000 ; Smaller receive loop timeout scalar
LD (RCVSCL),HL ; ... to compensate for BIOS overhead
;
LD HL,U_JPTBL
LD DE,U_LBL
LD HL,UB _JPTBL
LD DE,UB _LBL
JP MINIT_RET
;
;-----------------------------------------------------------------------
;
; Send character on top of stack
;
U_SENDR:
UB _SENDR:
POP AF ; get character to send from stack
PUSH BC
PUSH DE
@ -519,21 +534,24 @@ U_SENDR:
;
; Test and report carrier status, Z set if carrier present
;
U_CAROK:
UB _CAROK:
XOR A ; not used, always indicate present
RET
;
;-----------------------------------------------------------------------
;
; Get a character (assume character ready has already been tested)
; Get a character
;
; GETCHR must NOT block.
; GETCHR must not block
;
U_GETCHR:
CALL U_RCVRDY
UB _GETCHR:
CALL UB _RCVRDY
RET NZ
U_MDIN:
; Fall thru if char ready
;
; MDIN can assume a character is ready
;
UB_MDIN:
PUSH BC
PUSH DE
PUSH HL
@ -551,7 +569,7 @@ U_MDIN:
; Error code returned in A register
; *** Error code does not seem to be used ***
;
U_RCVRDY:
UB _RCVRDY:
PUSH BC
PUSH DE
PUSH HL
@ -570,7 +588,7 @@ U_RCVRDY:
;
; Test for ready to send a character, Z = ready
;
U_SNDRDY:
UB _SNDRDY:
PUSH BC
PUSH DE
PUSH HL
@ -588,7 +606,252 @@ U_SNDRDY:
;
; Report baud rate (index into SPTBL returned in register A)
;
U_SPEED:
UB_SPEED:
LD A,8 ; arbitrarily return 9600 baud
RET
;
;=======================================================================
;=======================================================================
;
; 8250-like UART
;
;=======================================================================
;=======================================================================
;
; UART constants
;
UA_SNDB EQU 20H ; bit to test for send ready
UA_SNDR EQU 20H ; value when ready to send
UA_RCVB EQU 01H ; bit to test for receive ready
UA_RCVR EQU 01H ; value when ready to receive
UA_PARE EQU 04H ; bit for parity error
UA_OVRE EQU 02H ; bit for overrun error
UA_FRME EQU 08H ; bit for framing error
UA_ERRS EQU UA_FRME | UA_OVRE | UA_PARE
;
; Following jump table is dynamically patched into real jump
; table at program startup. See MINIT above. Note that only a
; subset of the jump table is overlaid (SENDR to SPEED).
;
UA_JPTBL:
JP UA_SENDR ; send character (via pop psw)
JP UA_CAROK ; test for carrier
JP UA_MDIN ; receive data byte
JP UA_GETCHR ; get character from modem
JP UA_RCVRDY ; check receive ready
JP UA_SNDRDY ; check send ready
JP UA_SPEED ; get speed value for file transfer time
;
;-----------------------------------------------------------------------
;
; UART initialization
;
UA_INIT:
LD DE,13000 ; Receive loop timeout scalar
LD (RCVSCL),DE ; ... for UART RCVRDY timing
;
LD A,L ; Get base I/O port address
LD (UA_SCP),A ; Set port value in SENDR
LD (UA_GCP),A ; Set port value in GETCHR
ADD A,5 ; UART control port is 5 higher
LD (UA_RRP),A ; Set port value in RCVRDY
LD (UA_SRP),A ; Set port value in SNDRDY
;
LD HL,UA_JPTBL
LD DE,UA_LBL
JP MINIT_RET
;
;-----------------------------------------------------------------------
;
; Send character on top of stack
;
UA_SENDR:
POP AF ; get character to send from stack
OUT (0FFH),A ; send to port
UA_SCP EQU $-1 ; port value
RET
;
;-----------------------------------------------------------------------
;
; Test and report carrier status, Z set if carrier present
;
UA_CAROK:
XOR A ; not used, always indicate present
RET
;
;-----------------------------------------------------------------------
;
; Get a character
;
; GETCHR must not block
;
UA_GETCHR:
CALL UA_RCVRDY
RET NZ
; Fall thru if char ready
;
; MDIN can assume a character is ready
;
UA_MDIN:
IN A,(0FFH) ; read character from port
UA_GCP EQU $-1 ; port value
RET
;
;-----------------------------------------------------------------------
;
; Test for character ready to receive, Z = ready
; Error code returned in A register
; *** Error code does not seem to be used ***
;
UA_RCVRDY:
IN A,(0FFH) ; get modem status
UA_RRP EQU $-1 ; port value
AND UA_RCVB ; isolate ready bit
CP UA_RCVR ; test it (set flags)
LD A,0 ; report no line errors
;
RET
;
;-----------------------------------------------------------------------
;
; Test for ready to send a character, Z = ready
;
UA_SNDRDY:
IN A,(0FFH) ; get status
UA_SRP EQU $-1 ; port value
AND UA_SNDB ; isolate transmit ready bit
CP UA_SNDR ; test for ready value
RET
;
;-----------------------------------------------------------------------
;
; Report baud rate (index into SPTBL returned in register A)
;
UA_SPEED:
LD A,8 ; arbitrarily return 9600 baud
RET
;
;
;
UA_BASE DB 00H ; UART base port I/O address
UA_CTLP DB 00H ; UART control port I/O address
;
;
;=======================================================================
;=======================================================================
;
; WILL SOWERBUTTS ECB USB-FIFO
;
;=======================================================================
;=======================================================================
;
UF_BASE EQU 0CH
UF_DATA EQU (UF_BASE+0)
UF_STATUS EQU (UF_BASE+1)
UF_SEND_IMM EQU (UF_BASE+2)
;
; Following jump table is dynamically patched over initial jump
; table at program startup. See MINIT above. Note that only a
; subset of the jump table is overlaid (SENDR to SPEED).
;
UF_JPTBL:
JP UF_SENDR ; send character (via pop psw)
JP UF_CAROK ; test for carrier
JP UF_MDIN ; receive data byte
JP UF_GETCHR ; get character from modem
JP UF_RCVRDY ; check receive ready
JP UF_SNDRDY ; check send ready
JP UF_SPEED ; get speed value for file transfer time
;
;-----------------------------------------------------------------------
;
; USB-FIFO initialization
;
UF_INIT:
LD HL,12000 ; Receive loop timeout scalar
LD (RCVSCL),HL ; ... for UART RCVRDY timing
;
LD A,L ; Get base I/O port address (data port)
LD (UF_SCDP),A ; Set data port in SENDR
LD (UF_GCDP),A ; Set data port in GETCHR/MDIN
INC A ; Bump to status port
LD (UF_RRSP),A ; Set status port in RCVRDY
LD (UF_SRSP),A ; Set status port in SNDRDY
INC A ; Bump to send immediate port
LD (UF_SCIP),A ; Set send immed port in SENDR
;
LD HL,UF_JPTBL
LD DE,UF_LBL
JP MINIT_RET
;
;-----------------------------------------------------------------------
;
; Send character on top of stack
;
UF_SENDR:
POP AF ; get character to send from stack
OUT (0FFH),A ; write to fifo
UF_SCDP EQU $-1 ; data port
OUT (0FFH),A ; send immediate
UF_SCIP EQU $-1 ; send immediate port
RET
;
;-----------------------------------------------------------------------
;
; Test and report carrier status, Z set if carrier present
;
UF_CAROK:
XOR A ; not used, always indicate present
RET
;
;-----------------------------------------------------------------------
;
; Get a character (assume character ready has already been tested)
;
; GETCHR must not block
;
UF_GETCHR:
CALL UF_RCVRDY
RET NZ
; Fall thru if char ready
;
; MDIN can assume a character is ready
;
UF_MDIN:
IN A,(0FFH) ; get char
UF_GCDP EQU $-1 ; data port
RET
;
;-----------------------------------------------------------------------
;
; Test for character ready to receive, Z = ready
; Error code returned in A register
; *** Error code does not seem to be used ***
;
UF_RCVRDY:
IN A,(0FFH) ; b7=0 if char avail, =1 if no char.
UF_RRSP EQU $-1 ; status port
RLCA ; b0=0 if char avail, =1 if no char.
AND 00000001B ; a=0, zf=1 if no char, a=1, zf=0 if char avail.
LD A,0
RET
;
;-----------------------------------------------------------------------
;
; Test for ready to send a character, Z = ready
;
UF_SNDRDY:
IN A,(0FFH) ; bit 0=0 if space avail, =1 IF FULL
UF_SRSP EQU $-1 ; status port
AND 00000001B ; A=0, ZF=1 if space avail, A=1, ZF=0 if full.
RET
;
;-----------------------------------------------------------------------
;
; Report baud rate (index into SPTBL returned in register A)
;
UF_SPEED:
LD A,8 ; arbitrarily return 9600 baud
RET
;