magical/riscv-utils
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

lib/flags: progress

Browse Source
This commit is contained in:
magical 2023-05-24 22:23:41 -07:00
parent ba2d991765
commit 44d953a322
3 changed files with 181 additions and 71 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
Makefile
View File

@ -15,6 +15,7 @@ all: true false cat env hexdump echo
prtest: prtest.o lib/printregs.o lib/hex.o
sorttest: lib/sort.o
flagtest: lib/flags.o
.PHONY: test
test:

35
flagtest.s Normal file
View File

@ -0,0 +1,35 @@
.global _start
.extern init_flags
.extern parse_flags
.data
flags:
.dword 0 # value / default
.byte 1 # type: <end>, bool, string, int
.byte 5 # flag length
#.short 16 # help length
.ascii "-help"
#.ascii "prints help text"
# last flag
.dword 0
.dword 0
.text
_start:
.option push
.option norelax
la gp, __global_pointer$
.option pop
mv a0, sp
call init_flags
la a0, flags
call parse_flags
li a7, 93 # sys_exit
li a0, 0
ecall

216
lib/flags.s
View File

@ -1,4 +1,12 @@
.option norelax
.global init_flags
.global parse_flags
.macro subi dst, src, imm
addi \dst, \src, -\imm
.endm
.data
flags:
@ -19,6 +27,15 @@ entry_sp: .dword 0
saved_argc: .dword 0
saved_argv: .dword 0
.section .rodata
flag_failure_msg: .ascii "flag parsing failed\n\0"
.equ flag_failure_msg_len, (.) - flag_failure_msg
unknown_flag_msg: .ascii "unknown flag\n\0"
.equ unknown_flag_msg_len, (.) - unknown_flag_msg
.text
# when a program starts, it should stash the initial value of the sp register somewhere
# e.g.
#
@ -56,11 +73,13 @@ parse_flags:
ld a2, (a2)
tail parse_flags_args
# n.b. tail clobbers t1
# a0 - flag definition struct
# a1 - argc
# a2 - argv
parse_flags_args:
mv a7, ra
# TODO: positional arguments
# syntax:
@ -68,27 +87,53 @@ parse_flags_args:
# -flag value (only non-boolean flags)
# -flag=value
# main loop
# if argc <= 1, return
li t0, 1
bleu a1, t0, .Ldone
# main loop:
# for each argument, if it starts with a '-' then see if it matches a flag
mv s2, a2
# skip arg 0
addi s2, a2, 8
subi a1, a1, 1
.L_arg_loop:
ld s1, (s2) # load string pointer
beqz s1, .L_next_arg # skip null pointer
# check if first char is a '-'
ld t0, (s1)
beqz t0, .Lno # empty string
addi t0, t0, -'-'
bnez t0, .Lno # not a dash
lbu t0, 0(s1)
li t1, '-'
beq t0, t1, find_flag
.L_next_arg:
addi s2, s2, 8
subi a1, a1, 1
beqz a1, .Ldone
j .L_arg_loop
.Ldone:
mv ra, a7
ret
.Lunknown_flag:
mv ra, a7
li a7, 64 # sys_write
li a0, 2
la a1, unknown_flag_msg
li a2, unknown_flag_msg_len
ecall
li a0, -1
ret
# TODO: allow --flag
# TODO: -- should end flag parsing
find_flag:
mv s0, a0
.L_flag_loop:
lbu t3, 8(s0) # type
lbu t2, 9(s0) # flag length
beqz t2, .Lunknown_flag
lbu s3, 9(s0) # flag length
beqz s3, .Lunknown_flag # len=0 signifies the end of the flag definitions
call flagcmp
# return value:
# 0: no match
@ -97,42 +142,53 @@ parse_flags_args:
bnez t0, .Lfound
.L_next_flag:
addi s0, s0, 8
add s0, s0, t2
addi s0, s0, 10
add s0, s0, s3
j .L_flag_loop
.Lfound:
add t0, s1, t2 # arg+len
lbu t1, (t0)
beqz t1, 1f # is it a \0 or an =?
0:# move s1 past the =
addi t0, t0, 1
mv s1, t0
j 2f
1:# is this a boolean flag?
li t0, 1
beq t0, t3, 2f
subi t3, t3, 1
add s1, s1, s3 # arg+len
lbu t0, (s1)
beqz t0, 1f # is it a \0 or an =?
# =
# move s1 past the =
addi s1, s1, 1
j handle_flag
1:# \0
# is this a boolean flag? then there's no value
beqz t3, handle_flag
# if not, set s1 to the next arg and advance s2
ld s1, 8(s2)
addi s2, s2, 8
subi a1, a1, 1
# TODO: if it's null, that's an error
2:
# fallthrough
# s1 now points to the value of the flag
handle_flag:
# ok now parse the flag
.Lparse_flag:
lbu t3, 8(s0) # load type
li t0, 1
beq t0, t3, boolflag
li t0, 2
#lbu t3, 8(s0) # load type
beqz t3, boolflag
li t0, 2-1
beq t0, t3, strflag
li t0, 3
li t0, 3-1
beq t0, t3, intflag
j .Lbad_flag_def
strflag:
# easy, just store the string pointer
# TODO: strlen
sd s1, 0(s0)
j .L_next_arg
boolflag:
lbu t0, 0(s1)
# if arg is empty, set value to true
# TODO: should -bool and -bool= be treated differently?
beqz t0, 0f
# check for "true" and "false"
li t1, 'f'
@ -140,63 +196,56 @@ boolflag:
li t1, 't'
beq t0, t1, .Lboolcmptrue
# anything else is an error
j .Lboolbad
j .Lbadbool
.Lboolcmpfalse:
lbu t0, 1(s1)
beqz t0, .Lboolbad
beqz t0, .Lbadbool
li t1, 'a'
bne t1, t0, .Lboolbad
bne t1, t0, .Lbadbool
lbu t0, 2(s1)
beqz t0, .Lboolbad
beqz t0, .Lbadbool
li t1, 'l'
bne t1, t0, .Lboolbad
bne t1, t0, .Lbadbool
lbu t0, 3(s1)
beqz t0, .Lboolbad
beqz t0, .Lbadbool
li t1, 's'
bne t1, t0, .Lboolbad
bne t1, t0, .Lbadbool
lbu t0, 4(s1)
beqz t0, .Lboolbad
beqz t0, .Lbadbool
li t1, 's'
bne t1, t0, .Lboolbad
bne t1, t0, .Lbadbool
lbu t0, 5(s1)
bnez t0, .Lboolbad
j 0b
bnez t0, .Lbadbool
sd x0, 0(s0)
0:sd x0, 0(s0)
j .L_next_arg
.Lboolcmptrue:
lbu t0, 1(s1)
beqz t0, .Lboolbad
beqz t0, .Lbadbool
li t1, 'r'
bne t1, t0, .Lboolbad
bne t1, t0, .Lbadbool
lbu t0, 2(s1)
beqz t0, .Lboolbad
beqz t0, .Lbadbool
li t1, 'u'
bne t1, t0, .Lboolbad
bne t1, t0, .Lbadbool
lbu t0, 3(s1)
beqz t0, .Lboolbad
beqz t0, .Lbadbool
li t1, 'e'
bne t1, t0, .Lboolbad
bne t1, t0, .Lbadbool
lbu t0, 4(s1)
bnez t0, .Lboolbad
bnez t0, .Lbadbool
1:li t1, 1
sd t1, 0(s0)
j .L_next_arg
strflag:
# easy, just store the string pointer
# TODO: strlen
sd s1, 0(s0)
1:li t0, 1
sd t0, 0(s0)
j .L_next_arg
intflag:
@ -208,7 +257,7 @@ intflag:
li t2, 10
lbu t1, 0(s1)
beqz t1, .Lbadint
0:addi t1, t1, -0x30 # '0'
0:subi t1, t1, 0x30 # '0'
bltz t1, .Lbadint
bge t1, t2, .Lbadint
mul t0, t0, t2
@ -219,25 +268,50 @@ intflag:
1:sd t0, 0(s0)
j .L_next_arg
.L_next_arg:
ret
.Lbad_flag_def:
.Lbadint:
.Lboolbad:
.Lunknown_flag:
.Lbadbool:
mv ra, a7
li a7, 64
li a0, 2
la a1, flag_failure_msg
li a2, flag_failure_msg_len
ecall
li a0, -1
ret
# t4 - flag
# t5 -
# t6 length
# t0 - return
# in: s1 - string to compare, length unknown (null terminated)
# in: s0 - flag definition
# in: s3 - flag length
# out: t0 - match=1 no match=0
# clobbers t0, t1, t4, t5, t6, ra
flagcmp:
mv t0, zero
add t1, s0, 10 # flag
add t0, t1, s3 # end of flag
mv t4, s1 # str
3:lbu t5, (t1)
lbu t6, (t4)
bne t5, t6, 0f
# we don't _need_ to specifically check if t6==\0
# since that should be caught by the comparison above
# unless the flag contains an embedded \0 (it shouldn't)
# but do the check anyway just to be extra safe
beqz t6, 0f
addi t1, t1, 1
addi t4, t4, 1
# once we reach the end of the flag, we just need to check
# that the argument string ends in the same place
bge t1, t0, .Ltail
j 3b # loop
.Ltail:
lbu t1, (t4)
li t0, '='
beq t0, t1, 2f
beqz t1, 1f
0:mv t0, zero
ret
2:li t0, 2
ret
1:li t0, 1
ret
handle_flag: