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Refactor ROM Loader Baud Rate Change
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- The baud rate change functionality in ROM Loader was refactored to reduce it's size and be consistent with the approach used in the MODE command.
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@wwarthen
wwarthen committed Oct 16, 2024
1 parent b3a250b commit 42e5088
Showing 1 changed file with 124 additions and 134 deletions.
258 changes: 124 additions & 134 deletions Source/HBIOS/romldr.asm
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Original file line number Diff line number Diff line change
Expand Up @@ -31,7 +31,7 @@
; avoid the problem where the code is overlaid during the loading of
; the desired executable image.
;
#INCLUDE "std.asm" ; standard RomWBW constants
#include "std.asm" ; standard RomWBW constants
;
#ifndef BOOT_DEFAULT
#define BOOT_DEFAULT "H"
Expand Down Expand Up @@ -754,54 +754,15 @@ setcon:
call skipws ; skip whitespace
call isnum ; do we have a number?
jp nz,docon ; if no we don't change baudrate
call getbnum ; return in HL:BC
;
ld e,32 ; search baud rate table
push de ; for a matching entry
ld de,tbl_baud
nextbaud:
ex de,hl ; hl = tbl_baud, de = msw
ld a,d ; check all four bytes
cp (hl) ; against HL:BC
inc hl ; exit to next table
jr nz,mm1 ; entry on mismatch
ld a,e
cp (hl)
inc hl
jr nz,mm2
ld a,b
cp (hl)
inc hl
jr nz,mm3
ld a,c
cp (hl)
inc hl
jr nz,mm4
;
; we have a match
pop de ; get our count value
ld a,32
sub e
jr setspd
;
mm1: inc hl
mm2: inc hl
mm3: inc hl
mm4: ex (sp),hl ; hl = count value, stack = tbl_baud, de = msw
dec l
ex (sp),hl ; hl = tbl_baud, stack= count
ex de,hl ; hl = msw, de = tbl_baud
jr nz,nextbaud
;
; Failed to match
pop de
jp err_invcmd
;
setspd: ld (newspeed),a ; save validated baud rate
;
ld hl,str_chspeed ; notify user
call pstr ; to change
call cin ; speed
push de ; move char ptr
pop ix ; ... to IX
call getnum32 ; get 32-bit number
jp c,err_invcmd ; handle overflow
ld c,75 ; Constant for baud rate encode
call encode ; encode into C:4-0
jp nz,err_invcmd ; handle encoding error
ld a,c ; move encoded value to A
ld (newspeed),a ; save validated baud rate
;
; Get the current settings for chosen console
ld b,BF_CIOQUERY ; BIOS serial device query
Expand All @@ -815,12 +776,18 @@ setspd: ld (newspeed),a ; save validated baud rate
ld hl,newspeed ; and load in new
or (hl) ; baud rate
ld d,a
;
ld hl,str_chspeed ; notify user
call pstr ; to change speed
call ldelay ; time for line to flush
;
ld b,BF_CIOINIT ; BIOS serial init
ld a,(newcon) ; get serial device unit
ld c,a ; ... into C
rst 08 ; call HBIOS
jp nz,err_invcmd ; handle error
;
call cin ; wait for char at new speed
;
; Notify user, we're outta here....
docon: ld hl,str_newcon ; new console msg
Expand All @@ -842,90 +809,6 @@ docon: ld hl,str_newcon ; new console msg
call pstr ; do it
ret
;
;=======================================================================
; Get numeric chars at DE and convert to BCD number returned in HL:BC
;=======================================================================
;
getbnum:ld bc,0 ; lsw
ld hl,0 ; msw
getbnum1:
ld a,(de) ; get the active char
cp '0' ; compare to ascii '0'
jr c,getbnum2 ; abort if below
cp '9' + 1 ; compare to ascii '9'
jr nc,getbnum2 ; abort if above
;
sub '0' ; convert '0'-'9' to 0-9
;
push de ; save char posn
push hl ; save hl bcd
;
ld hl,tmpbcd ; rotate 1 nyble in A
ld (hl),c ; through HL:BC
rld
ld c,(hl)
ld (hl),b
rld
ld b,(hl)
pop de ; get hl bcd
ld (hl),e
rld
ld e,(hl)
ld (hl),d
rld
ld d,(hl)
ld h,d
ld l,e
;
pop de ; get char posn
inc de ; bump to next char
jr getbnum1 ; loop
;
getbnum2:
or a ; with flags set, CF is cleared
ret
;
tmpbcd: .db 0
;
#DEFINE PACK(a,b,c,d,e,f,g) \
#DEFCONT \ .db (16*('0'-'0'))+(a-'0'))
#DEFCONT \ .db (16*(b-'0'))+(c-'0'))
#DEFCONT \ .db (16*(d-'0'))+(e-'0'))
#DEFCONT \ .db (16*(f-'0'))+(g-'0'))
;
tbl_baud:
PACK('0','0','0','0','0','7','5') ; 75 0 > 0
PACK('0','0','0','0','1','5','0') ; 150 1 > 1
PACK('0','0','0','0','3','0','0') ; 300 3 > 2
PACK('0','0','0','0','6','0','0') ; 600 5 > 3
PACK('0','0','0','1','2','0','0') ; 1200 7 > 4
PACK('0','0','0','2','4','0','0') ; 2400 9 > 5
PACK('0','0','0','4','8','0','0') ; 4800 11 > 6
PACK('0','0','0','9','6','0','0') ; 9600 13 > 7
PACK('0','0','1','9','2','0','0') ; 19200 15 > 8
PACK('0','0','3','8','4','0','0') ; 38400 17 > 9
PACK('0','0','7','6','8','0','0') ; 76800 19 > 10
PACK('0','1','5','3','6','0','0') ; 153600 21 > 11
PACK('0','3','0','7','2','0','0') ; 307200 23 > 12
PACK('0','6','1','4','4','0','0') ; 614400 25 > 13
PACK('1','2','2','8','8','0','0') ; 1228800 27 > 14
PACK('2','4','5','7','6','0','0') ; 2457600 29 > 15
PACK('0','0','0','0','2','2','5') ; 225 2 > 16
PACK('0','0','0','0','4','5','0') ; 450 4 > 17
PACK('0','0','0','0','9','0','0') ; 900 6 > 18
PACK('0','0','0','1','8','0','0') ; 1800 8 > 19
PACK('0','0','0','3','6','0','0') ; 3600 10 > 20
PACK('0','0','0','7','2','0','0') ; 7200 12 > 21
PACK('0','0','1','4','4','0','0') ; 14400 14 > 22
PACK('0','0','2','8','8','0','0') ; 28800 16 > 23
PACK('0','0','5','7','6','0','0') ; 57600 18 > 24
PACK('0','1','1','5','2','0','0') ; 115200 20 > 25
PACK('0','2','3','0','4','0','0') ; 230400 22 > 26
PACK('0','4','6','0','8','0','0') ; 460800 24 > 27
PACK('0','9','2','1','6','0','0') ; 921600 26 > 28
PACK('1','8','4','3','2','0','0') ; 1843200 28 > 29
PACK('3','6','8','6','4','0','0') ; 3686400 30 > 30
PACK('7','3','7','2','8','0','0') ; 7372800 31 > 31
#endif
;
; Set RomWBW HBIOS Diagnostic Level
Expand Down Expand Up @@ -1514,10 +1397,13 @@ pvol1:
nl2:
call nl ; double newline
nl:
push af
ld a,cr ; cr
call cout ; send it
ld a,lf ; lf
jp cout ; send it and return
call cout ; send it and return
pop af
ret
;
; Print a dot on console
;
Expand Down Expand Up @@ -1929,6 +1815,110 @@ hexconv:
daa
ret
;
#if (BIOS == BIOS_WBW)
;
; Get numeric chars and convert to 32-bit number returned in DE:HL
; IX points to start of char buffer
; Carry flag set on overflow
;
getnum32:
ld de,0 ; Initialize DE:HL
ld hl,0 ; ... to zero
getnum32a:
ld a,(ix) ; get the active char
cp '0' ; compare to ascii '0'
jr c,getnum32c ; abort if below
cp '9' + 1 ; compare to ascii '9'
jr nc,getnum32c ; abort if above
;
; valid digit, multiply DE:HL by 10
; X * 10 = (((x * 2 * 2) + x)) * 2
push de
push hl
;
call getnum32e ; DE:HL *= 2
jr c,getnum32d ; if overflow, ret w/ CF & stack pop
;
call getnum32e ; DE:HL *= 2
jr c,getnum32d ; if overflow, ret w/ CF & stack pop
;
pop bc ; DE:HL += X
add hl,bc
ex de,hl
pop bc
adc hl,bc
ex de,hl
ret c ; if overflow, ret w/ CF
;
call getnum32e ; DE:HL *= 2
ret c ; if overflow, ret w/ CF
;
; now add in new digit
ld a,(ix) ; get the active char
sub '0' ; make it binary
add a,l ; add to L, CF updated
ld l,a ; back to L
jr nc,getnum32b ; if no carry, done
inc h ; otherwise, bump H
jr nz,getnum32b ; if no overflow, done
inc e ; otherwise, bump E
jr nz,getnum32b ; if no overflow, done
inc d ; otherwise, bump D
jr nz,getnum32b ; if no overflow, done
scf ; set carry flag to indicate overflow
ret ; and return
;
getnum32b:
inc ix ; bump to next char
jr getnum32a ; loop
;
getnum32c:
; successful completion
xor a ; clear flags
ret ; and return
;
getnum32d:
; special overflow exit with stack fixup
pop hl ; burn 2
pop hl ; ... stack entries
ret ; and return
;
getnum32e:
; DE:HL := DE:HL * 2
sla l
rl h
rl e
rl d
ret
;
; Integer divide DE:HL by C
; result in DE:HL, remainder in A
; clobbers F, B
;
div32x8:
xor a
ld b,32
div32x8a:
add hl,hl
rl e
rl d
rla
cp c
jr c,div32x8b
sub c
inc l
div32x8b:
djnz div32x8a
ret
;
DIV32X8 .equ div32x8
;
#include "encode.asm" ; baud rate encoding routine
;
encode .equ ENCODE
;
#endif
;
;=======================================================================
; Console character I/O helper routines (registers preserved)
;=======================================================================
Expand Down

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