Samsung S5PC100, User Manual

Page: 1292 / 1863

S5PC100 USER’S MANUAL (REV1.0) 3D-ACCELERATOR
9.6-65
7.1.8 Special Function Register For Hw Configuration (FGPS) (PS_ PCEND, R/W, ADDRESS =
0X0004_C808)
PS_PCEnd Bit Description Reset Value
Reserved [31:10] Reserved 0
PS_IgnorePCEnd [9] When this bit is set to 1, PS_PCEnd value is ignored and the
only program counter stack empty condition is used for program
termination. 0
PS_PCEnd [8:0] When the program counter is reached at the value of
PS_PCEnd, the shader program is terminated after execution of
the instruction at this register. This method can save instruction
slot and number of instruction count to execute.
The other way to terminate pixel shader program :
Pixel shader program can be terminated by the extra “ret”
instruction which makes program counter stack empty condition.
Usually, “call” and “ret” instruction works a pair. But the
intentional unmatched “ret” makes pixel shader termination
condition. By this exception, pixel shader program can be
terminated.
0x1FF
7.1.9 Special Function Register For Hw Configuration (FGPS) (PS_ PCCOPY, R/W, ADDRESS =
0X0004_C80C)
PS_PCCopy Bit Description Reset Value
Reserved [31:1] Eeserved 0
PS_PCCopy [0] When this bit is set to ‘1’, PS_PCStart register value is actually
copied to the pixel shader inside. This bit is auto cleared to ‘0’
after copy.
Without copy command, the value of PS_PCStart is not used,
and the previous value is used for program start.
0b