Commit f0f26a06d51b7e7764f8951cdbf67ac9ad507f6d

Authored by Blue Swirl
1 parent d084469c

Update docs on dynamic condition code calculation

Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
Showing 1 changed file with 5 additions and 3 deletions
qemu-tech.texi
... ... @@ -363,7 +363,9 @@ look at @code{tcg/README}.
363 363 Lazy evaluation of CPU condition codes (@code{EFLAGS} register on x86)
364 364 is important for CPUs where every instruction sets the condition
365 365 codes. It tends to be less important on conventional RISC systems
366   -where condition codes are only updated when explicitly requested.
  366 +where condition codes are only updated when explicitly requested. On
  367 +Sparc64, costly update of both 32 and 64 bit condition codes can be
  368 +avoided with lazy evaluation.
367 369  
368 370 Instead of computing the condition codes after each x86 instruction,
369 371 QEMU just stores one operand (called @code{CC_SRC}), the result
... ... @@ -376,8 +378,8 @@ conditional branches.
376 378 @code{CC_OP} is almost never explicitly set in the generated code
377 379 because it is known at translation time.
378 380  
379   -The lazy condition code evaluation is used on x86, m68k and cris. ARM
380   -uses a simplified variant for the N and Z flags.
  381 +The lazy condition code evaluation is used on x86, m68k, cris and
  382 +Sparc. ARM uses a simplified variant for the N and Z flags.
381 383  
382 384 @node CPU state optimisations
383 385 @section CPU state optimisations
... ...