I think Martin is really commenting that if you only have 3 branch
possibilities, then the overhead of the validation is greater than just
doing three Test-and-branch instruction pairs.
I don't know about others, but I don't usually use a branch table unless
I have 8 or more values. Many of my branch tables have 100+ entries.
Tony Thigpen
Seymour J Metz wrote on 11/23/21 12:31 PM:
?
What is a shorter way to do the error checking?
--
Shmuel (Seymour J.) Metz
http://mason.gmu.edu/~smetz3
________________________________________
From: IBM Mainframe Assembler List [ASSEMBLER-LIST@LISTSERV.UGA.EDU] on behalf
of Martin Ward [mar...@gkc.org.uk]
Sent: Tuesday, November 23, 2021 12:27 PM
To: ASSEMBLER-LIST@LISTSERV.UGA.EDU
Subject: Re: Base-less macros
On 23/11/2021 17:12, Seymour J Metz wrote:
LTR R15,R15
JM BADIX
CHI R15,LIMIT
JH BADIX
TML R15,3
JNZ BADIX
J *+4(R15)
BRTAB EQU *
J RC0ROUTINE
J RC4ROUTINE
J RC8ROUTINE
LIMIT EQU *-BRTAB
Three test and branch instruction pairs plus two unconditional
branch instructions, all to avoid executing a sequence
of up to three test and branch instruction pairs :-)
--
Martin
Dr Martin Ward | Email: mar...@gkc.org.uk |
http://secure-web.cisco.com/1Pzh0mz_8aE1yk4Zn65QdgWKxjXTYuplR0LTSWVThm5eBwv_XGYMaTUu-chekxBfi6Q9025E8Qko7Tv2AfAq4VKpPXZJATEnvK9yfCADRqS-MqJ-9CwXhQPcVAUaaVJisVYqePQcB1EgYhTEXUg6EMsRZGoSZYmbdXVC6DKXq6U8r16EOSntjBUqgbf2JkfOl98-JPqYFjgE8_O2ukkHD0bNk7EcYVFjZpL1RJqnISm5qT4Y1PLZTFqF7W4RLN3SouhBZKmQy9KILd6gufPlqfnEZ6XXLr886LHYJ7D4RI2pkwR_tUPju4DD8dBYH0dI5vbdm4BN1zPlh0lAnJdlARc5rcXUCQ658_9kIqdQ2ssUV8SW7IqhNvqBrN5QJARIDeNc6W-Q-LfKdo7Pk9GyTpPv0B3hR9SkveNdRnWPBZDBmkTzbbHhclfSRqf0xnmsZ/http%3A%2F%2Fwww.gkc.org.uk
G.K.Chesterton site:
http://secure-web.cisco.com/1OoGY6MPQRndcjIvC1a1r8dwvjRs0IiXumRn9B23l7Qi4vovkS4Ad8DCdEzjy7ZIxLBepUzkEB_3bndzCEBbgp6ItZFwrsQSie-z0aU7oWtR4pD-YS5UwnfKWFfEM53hm7XEj8GMpX_xgRvBYE6TI0wql6IHyekYniK7_TXAPyRNm18FqTVb_EXc24xGkuM4ixs2eE2TlFlZFIZKuIvQCgjZs600JXzVB2Caqp-MsKzLomt4z2p5Y3oxjZF9k0tWw8BKgGSN-e2OHTuv1dZfxbT7sMdFq0_P0TneTPOkY5JnRjmQK04uRe9mgyNatqGClUiwzLK4C7cShMxI2X-pM21gz0CRfnAG77jKiBGCgCVy-6Qak1MF7G9FPhX9rdPIB8sOIEruuQuHWc0VVU9Ps4UvPqQIKmmIbtqJ76rIR9-r-TwsRyxErjP4aJaZlW7MQ/http%3A%2F%2Fwww.gkc.org.uk%2Fgkc
| Erdos number: 4
